Epidemiology of and Risk Factors for Coronavirus Infection in Health Care Workers: A Living Rapid ReviewFREE
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Abstract
An update is available for this article.
Background:
Health care workers (HCWs) are at risk for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.
Purpose:
To examine the burden of SARS-CoV-2, SARS-CoV-1, and Middle East respiratory syndrome (MERS)-CoV on HCWs and risk factors for infection, using rapid and living review methods.
Data Sources:
Multiple electronic databases, including the WHO database of publications on coronavirus disease and the medRxiv preprint server (2003 through 27 March 2020, with ongoing surveillance through 24 April 2020), and reference lists.
Study Selection:
Studies published in any language reporting incidence of or outcomes associated with coronavirus infections in HCWs and studies on the association between risk factors (demographic characteristics, role, exposures, environmental and administrative factors, and personal protective equipment [PPE] use) and HCW infections. New evidence will be incorporated on an ongoing basis by using living review methods.
Data Extraction:
One reviewer abstracted data and assessed methodological limitations; verification was done by a second reviewer.
Data Synthesis:
64 studies met inclusion criteria; 43 studies addressed burden of HCW infections (15 on SARS-CoV-2), and 34 studies addressed risk factors (3 on SARS-CoV-2). Health care workers accounted for a significant proportion of coronavirus infections and may experience particularly high infection incidence after unprotected exposures. Illness severity was lower than in non-HCWs. Depression, anxiety, and psychological distress were common in HCWs during the coronavirus disease 2019 outbreak. The strongest evidence on risk factors was on PPE use and decreased infection risk. The association was most consistent for masks but was also observed for gloves, gowns, eye protection, and handwashing; evidence suggested a dose–response relationship. No study evaluated PPE reuse. Certain exposures (such as involvement in intubations, direct patient contact, or contact with bodily secretions) were associated with increased infection risk. Infection control training was associated with decreased risk.
Limitation:
There were few studies on risk factors for SARS-CoV-2, the studies had methodological limitations, and streamlined rapid review methods were used.
Conclusion:
Health care workers experience significant burdens from coronavirus infections, including SARS-CoV-2. Use of PPE and infection control training are associated with decreased infection risk, and certain exposures are associated with increased risk.
Primary Funding Source:
World Health Organization.
A cluster of pneumonia cases in Wuhan, China, was first reported to the World Health Organization (WHO) on 31 December 2019 (1). The cause was identified as the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (2–4), and the disease was named “coronavirus disease 2019” (COVID-19) (5).
Health care workers (HCWs) are at risk for SARS-CoV-2 infection (6), and reports have described COVID-19 cases in HCWs since early in the outbreak (7). Preventing HCW infections is important for reducing morbidity and potential mortality, maintaining health system capacity, and reducing secondary transmission (8, 9).
This rapid review summarizes the evidence on the burden of and risk factors for SARS-CoV-2 infections in HCWs. The report will be used by WHO to inform the development of evidence-based guidance. Because evidence is limited on SARS-CoV-2, this review also includes 2 coronaviruses associated with earlier pneumonia outbreaks: SARS-CoV-1 (causing severe acute respiratory syndrome [SARS-1]) and MERS-CoV (causing Middle East respiratory syndrome [MERS]).
Methods
Detailed methods are available in the full report (10). The key questions were developed by WHO with input from the review authors.
Key Question 1. What is the burden of SARS-CoV-2, SARS-CoV-1, and MERS-CoV on HCWs and how do burdens vary according to age, sex, and presence of comorbidities?
Key Question 2. What are the risk factors for HCW infections with SARS-CoV-2, SARS-CoV-1, and MERS-CoV?
Key Question 3. What are the risk factors for household transmission of SARS-CoV-2, SARS-CoV-1, and MERS-CoV from HCWs?
Because of the urgent and ongoing need to support WHO's pandemic response, a rapid, living review approach was used (11). Rapid reviews utilize streamlined systematic review processes. For this review, modified methods included 1) protocol not posted to a systematic review registry; 2) a gray literature search limited to 1 website; 3) dual review of 25% of abstracts; 4) critical appraisal not conducted using a formal instrument; and 5) single-reviewer assessment of study limitations and data abstraction, with second reviewer verification. Living reviews use methods for continual updating, as new evidence becomes available (12).
Data Sources and Searches
A medical librarian searched PubMed, MEDLINE, and Embase (from 2003 through 27 March 2020). Searches had no language restrictions. Search strategies are shown in Appendix Table 1. We also searched the WHO database on coronavirus disease (13) and the medRxiv preprint server (14) and reviewed reference lists. Daily MEDLINE surveillance and weekly surveillance on Embase, the WHO database on coronavirus disease, and the medRxiv server is ongoing; this article includes surveillance through 24 April 2020.
Study Selection
Studies were selected by using predefined criteria (Appendix Table 2). The population was HCWs at risk for or with SARS-CoV-2, SARS-CoV-1, or MERS-CoV infection. For key question 1, for SARS-CoV-2, we included cohort studies and case series on incidence and severity of infection, mortality, morbidity (including mental health outcomes), and effects on family members and contacts. For SARS-CoV-1 and MERS-CoV, inclusion was restricted to cohort studies on incidence, infection severity, and mortality. For key question 2, potential risk factors were demographic characteristics, exposure history, administrative factors, health care setting/environmental factors, HCW health, and infection control and prevention factors. We included studies that reported risk estimates or infection incidence stratified by risk factor.
One investigator reviewed each citation for potential full-text review. A second investigator reviewed a 25% random sample of citations; disagreements were resolved through consensus. One investigator reviewed each full-text article for inclusion, and a second verified exclusion decisions. We included non–peer-reviewed articles for SARS-CoV-2 because the peer-reviewed literature was sparse. Chinese-language articles were translated by a review team member who was a native speaker.
Data Extraction
One investigator extracted study data into standardized tables and a second verified data: study author, year, setting (country, health care setting, dates), population characteristics (sample size, age, sex, HCW role/position, number of cases), and results. For key question 2, odds ratios (ORs) were calculated if necessary and if the data were available.
Quality Assessment
Data Synthesis and Analysis
Results were synthesized narratively. For key question 2, unadjusted and adjusted risk estimates were presented. Quantitative synthesis was not possible owing to methodological limitations; study design variability; and heterogeneity in populations, comparisons, and analytic methods.
Living Review
Surveillance for new studies is ongoing, and study selection and quality assessment will follow the same processes described. New evidence that does not substantively change review conclusions will be briefly summarized on a monthly basis; a major update will be performed when new evidence changes the nature or strength of the conclusions.
Role of the Funding Source
The study was funded by the WHO. Staff at the WHO developed the key questions and review scope but did not have any role in the selection, assessment, or synthesis of evidence. The WHO was not involved in the decision to submit this article for publication.
Results
Sixty-four studies met inclusion criteria (17–80). The Appendix Figure summarizes the study selection process and number of included studies, by key question and coronavirus type.
Appendix Figure. Literature search and selection.
CoV = coronavirus; KQ = key question; MERS = Middle East respiratory syndrome; SARS = severe acute respiratory syndrome.
* Some studies were included for multiple KQs; includes 6 studies that were not peer-reviewed (28, 39, 46, 47, 59, 79) and 3 Chinese-language studies translated into English (48, 52, 78).
† Data from 2 World Health Organization websites on the incidence of SARS-1 (81) and MERS (82) were also included.
‡ Included in the full evidence review (10).
Key Question 1: Burden of Coronavirus Infections on HCWs
SARS-CoV-2
One cohort study (61), 9 cross-sectional studies (28, 36, 39, 40, 46, 51, 59, 79, 80), and 5 case series (47, 48, 53, 67, 68) reported on the burden of SARS-CoV-2 in HCWs (Appendix Table 3).
Two non–peer-reviewed, retrospective cohort studies reported the proportion of exposed HCWs with polymerase chain reaction (PCR)–confirmed SARS-CoV-2 infection (39, 61). One study evaluated 1353 HCWs in the Netherlands with recent fever or mild respiratory symptoms. Infection with SARS-CoV-2 was present in 6.4% (86 of 1353) of the HCWs; 91.9% (79 of 86) of infections met the COVID-19 case definition. Two HCWs (3.7% [2 of 86]) were hospitalized, with no critical cases or deaths. A second, smaller study of 72 exposed HCWs with acute symptoms in Wuhan, China, reported a COVID-19 incidence of 38.9% (61).
Health care workers accounted for 3.8% (1716 cases) of 44 672 cases of COVID-19 (PCR-confirmed) diagnosed in China through 11 February 2020 (67). The proportion of HCW cases classified as severe or critical was 15% (247 of 1608), and the case-fatality rate was 0.3% (5 of 1716). Health care workers accounted for a higher proportion of cases from 11 to 20 January (5.7%), early in the outbreak when case numbers were increasing sharply. The proportion of cases that were severe or critical was highest from 1 to 10 January (45% [9 of 20]) and lowest after 1 February (8.7% [28 of 322]).
Another non–peer-reviewed study evaluated a large series of 25 961 patients with PCR-confirmed COVID-19 diagnosed in Wuhan, China, through 18 February 2020 (68). Health care workers accounted for 5.1% (1316 of 25 961) of cases. The overall estimated COVID-19 incidence, using epidemiologic data for denominators, was higher in HCWs than the general population (144.7 [95% CI, 137.0 to 152.8] vs. 41.7 [CI, 41.2 to 42.2] per 106 people) (Appendix Table 3).
Three case series reported outcomes of COVID-19 infections in HCWs (47, 48, 53). Two separate series (50 and 64 HCWs) reported on infected HCWs in Wuhan, China (47, 48). The average age (35 years) and proportion of females (~65%) were similar. In one study, one third of cases were physicians and two thirds were nurses; this was reversed in the other study. There were no deaths. In one study, 1.6% (1 of 64) of HCWs had severe illness not requiring mechanical ventilation (47). In the other study, 13.3% (4 of 30) met criteria for severe pneumonia and received noninvasive ventilation or nasal high-flow oxygen (48). A limitation of the studies is that 20% and 47% of cases remained hospitalized at outcome assessment. In addition, in 1 study, few cases (25% [7 of 30]) were PCR-confirmed (48). The third study found that 29% (50 of 167) of cases in a U.S. long-term care facility were HCWs (53). The median age was 43.5 years, and 76% were female. Six percent (3 of 50) of HCWs were hospitalized, with no deaths.
Seven cross-sectional studies (16 630 HCWs) evaluated the mental health or sleep quality of HCWs in China during the COVID-19 outbreak (28, 36, 40, 46, 51, 59, 80). The proportion of HCWs meeting clinically relevant (that is, moderate or severe) thresholds was 14% to 15% for depression (40, 80), 12% to 24% for anxiety (40, 46, 80), 30% to 39% for psychological distress (28, 40, 80), 8% to 60% for sleep issues (40, 59), and 29% (36) for a composite mental health outcome. Female sex (28, 40, 80) and direct contact with cases (40, 46, 51, 80) were associated with increased likelihood of mental health issues; effect of HCW role on risk was inconsistent (28, 36, 80). Methodological limitations included no baseline symptom information, no non-HCW comparison groups, and not controlling for work exposures. One cross-sectional study (843 persons) found a high prevalence of anxiety (34%) and psychological distress (29%) in family members of HCWs (79).
No study reported the social or economic effects of SARS-CoV-2 infection in HCWs or the incidence of HCW transmission to close contacts.
SARS-CoV-1
Fourteen cohort studies (25, 30, 32–35, 43, 45, 50, 57, 60, 64, 69, 74), 1 cross-sectional study (27), and 1 case series (44) reported on the burden of SARS-CoV-1 in HCWs (Appendix Table 3). We also included WHO data (81).
The prevalence of SARS-CoV-1 seropositivity in exposed or potentially exposed HCWs ranged from 0.3% to 40% in 6 studies (25, 27, 33, 57, 60, 69), and SARS-1 incidence ranged from 1.2% to 29.4% in 14 studies (25, 30, 32–35, 43, 45, 50, 57, 60, 64, 69, 74). The highest SARS-1 incidence (29.4%) occurred in a large outbreak in Vietnam in a hospital without an isolation ward (57). In addition, infection control measures were not initiated owing to unawareness of the index SARS-1 case. Another study reporting high incidence focused on critical care nurses in Canada who cared for patients with SARS-1 with unstandardized PPE use, often before knowing patients' infection status (50).
Health care workers accounted for 21% (1706 of 8096) of all SARS-1 cases reported to WHO (Appendix Table 4). Among countries with at least 50 cases, HCWs accounted for 19% (China) to 57% (Vietnam). Among all (n = 1755) SARS-1 cases from Hong Kong, the case-fatality rate in HCWs was 2.0% (8 of 405), compared with 21.8% (294 of 1350) in non-HCWs (adjusted OR, 0.3 [CI, 0.1 to 0.7]) (Appendix Table 3) (44).
MERS-CoV
Seven cohort studies (18, 19, 21, 37, 38, 63, 71), 4 case series (17, 20, 22, 29), and 1 cross-sectional study (54) reported on the burden of MERS in HCWs (Appendix Table 3). We also utilized WHO data (82).
In 3 studies with at least 500 HCWs (3311 HCWs in total), the proportion with MERS-CoV infection ranged from 1.12% to 2.0% (21, 37, 54). In 5 smaller studies (9 to 283 HCWs), the proportion ranged from 0% to 7.1% (18, 19, 38, 63, 71).
As of December 2019, HCWs accounted for 19.1% (402 of 2106) of laboratory-confirmed cases of MERS in Saudi Arabia, which accounts for 84% of cases (Appendix Table 4) (82). Globally, among the 651 MERS cases diagnosed in July to December, 14% to 18% were HCWs in 2014 and 2015 and 0% to 4% in 2018 and 2019.
An analysis of all cases of MERS in HCWs reported to WHO found an overall case-fatality rate of 5.8% (24 of 415); excluding primary cases, mortality was slightly lower (4.7%) (29). These figures are lower than the overall MERS case-fatality rate (34.4%) (82). Two smaller case series (166 and 105 HCWs) reported HCW case-fatality rates of 3.0% and 16% (17, 20). Studies that directly compared MERS mortality in HCWs versus non-HCWs also reported lower mortality risk in HCWs (17, 20, 22). In the largest analysis (2260 HCWs), the adjusted OR was 0.07 (CI, 0.001 to 0.35) (22). Factors associated with increased mortality risk in HCWs are older age and presence of comorbid conditions (22, 29).
Key Question 2: Risk Factors for Coronavirus Infection in HCWs
SARS-CoV-2
Three retrospective cohort studies evaluated risk factors for COVID-19 in exposed HCWs (Appendix Table 5) (55, 61, 70). One study evaluated risk factors for COVID-19 in 72 exposed HCWs (clinicians and nurses) in Wuhan, China, who had acute symptoms (61). The median age was 31 years, and 69% of HCWs were female; PCR-confirmed COVID-19 occurred in 38.9% (28 of 72 HCWs). Risk factors were working in a high risk versus general department (relative risk [RR], 2.13 [CI, 1.45 to 3.95]), suboptimal handwashing before or after patient contact (RR, 3.10 [CI, 1.43 to 6.73] and 2.82 [CI, 1.11 to 7.18], respectively), longer work hours (log-rank P = 0.02), and improper PPE use (RR, 2.82 [CI, 1.11 to 7.18]). Such procedures as endotracheal tube removal, cardiopulmonary resuscitation, fiberoptic bronchoscopy, and sputum suction were not associated with increased risk. Having a diagnosed family member was associated with increased risk (RR, 2.76 [CI, 2.02 to 3.77]), suggesting that some HCW infections may have been acquired outside the hospital. The study was susceptible to recall bias, it was unclear whether risk estimates were adjusted, and some estimates were imprecise.
Another study evaluated 41 HCWs exposed to a patient with COVID-19 and an aerosol-generating procedure for 10 or more minutes at a distance of 2 meters or less (55). Eighty-five percent of HCWs used a surgical mask, and 15% used an N95 respirator. No COVID-19 cases occurred; therefore, it was not possible to draw conclusions about effects of mask type. One other study reported a strong association between N95 respirator use and decreased COVID-19 risk but had serious limitations (70). Mask use was based on the department worked (not on individual use), departments varied in other infection control measures (such as handwashing), and estimates were very imprecise.
SARS-CoV-1
Seventeen cohort studies (23, 25, 30, 32–35, 43, 45, 50, 57, 60, 64, 69, 72, 75, 77), 11 case–control studies (26, 41, 49, 52, 56, 58, 62, 65, 66, 76), and one cross-sectional study (27) evaluated risk factors for SARS-CoV-1 infection in HCWs (Appendix Table 5). Seven studies evaluated risk for SARS-CoV-1 seropositivity not necessarily meeting the SARS-1 case definition (25–27, 33, 60, 69, 72). The remainder evaluated risk for SARS-1 meeting the case definition, usually with laboratory confirmation. Ten studies reported adjusted risk estimates from multivariate models (26, 41, 49, 52, 57, 58, 60, 66, 76, 78). Of these, 2 studies evaluated correlations between risk factors (for example, between use of different types of PPE) to inform variable selection for model building (49, 76). All studies except for 1 (32) were retrospective. The studies were limited in their ability to measure and control for the amount and intensity of exposures.
Age and Sex.
Six studies indicated no association between sex and risk for SARS-CoV-1 infection in HCWs (Appendix Table 6) (27, 56, 60, 66, 69). One study found no association between age and risk for SARS-CoV-1 infections after controlling for other factors (adjusted OR, 0.97 [CI, 0.90 to 1.03]) (57). Five other studies that did not control for confounders also found no association between age and risk for SARS-CoV-1 infection (27, 56, 60, 66).
Professional Profile.
Twelve studies reported SARS-CoV-2 infection incidence by HCW role (Appendix Table 6) (25, 27, 30, 32, 34, 43, 52, 56, 57, 60, 69). Infections occurred in HCWs across various clinical and nonclinical (including nonpatient contact) roles. There was no consistent difference in risk between nurses and physicians, the most commonly evaluated HCW roles, based on 12 studies (25, 27, 30, 32, 34, 43, 45, 52, 56, 57, 60, 69). There were too few studies and cases to determine risks for other HCW roles relative to nurses and physicians.
Exposure History.
Exposure during endotracheal intubation was strongly and consistently associated with increased risk for HCW SARS-CoV-1 infections in 6 studies (Table 1) (26, 30, 49, 50, 58, 60). Of these, 4 studies found exposure during endotracheal intubation to be independently associated with risk (26, 30, 58, 60). One study (50) found oxygen mask manipulation to be associated with increased risk for infection in a univariate analysis, but 2 other studies (60, 66) found that oxygen mask manipulation or oxygen administration were not independent predictors. Few studies evaluated risks associated with other procedures involving oxygen administration, such as noninvasive positive-pressure ventilation (30, 50, 60), high-frequency oscillatory ventilation (30), nebulizer treatment (50, 60), manual ventilation (50), high-flow oxygen (60), or mechanical ventilation (60), and estimates were often imprecise. Other procedures associated with increased risk but only evaluated in 1 or 2 studies each were electrocardiography (50, 60), chest compressions (49, 60), and suctioning before intubation (50). In most studies, direct patient contact was associated with increased risk compared with less direct contact, though some inconsistency was present (26, 33, 41, 49, 57, 58, 62, 66, 72). Other exposures associated with increased risk for infections in HCWs were exposure of eyes or mucous membranes to patient bodily fluids (60, 64), contact with more severely ill patients (60), contact with a “super spreading” patient (26), closer proximity to infected patients (58, 62, 64, 75), and contact with respiratory secretions (49, 52). Evidence on the association between duration of contact with patients and risk for infection was inconsistent (52, 60, 64, 66).
Administrative Factors.
One study found administrative measures (having a crisis response team, exclusion of visitors, or provision of administrative support) and PPE use policies (requiring N95 respirator in the emergency department, within certain hospital zones, or on entering the hospital) were not associated with risk for HCW infections (Appendix Table 7) (76). Another study (with the same lead author) found a lower incidence of HCW infections in a hospital in which an integrated infection control strategy was implemented compared with 86 control hospitals, but did not control for use of infection control measures or degree of SARS-1 exposure (77).
Health Care Setting and Environmental Factors.
One study of hospitals found installation of a fever screen station outside of the emergency department and alcohol dispensers for hand sanitation to be associated with decreased likelihood of HCW SARS-1 infections (adjusted OR, 0.05 [CI, 0.004 to 0.692] and 0.043 [CI, 0.003 to 0.63], respectively) (Appendix Table 7) (76). One study found a higher risk for infections in the emergency department compared with hospital wards (69), and 1 study reported HCW infections in multiple hospital departments (27). Natural air ventilation was associated with decreased risk for SARS-CoV-1 infection versus artificial ventilation in 1 study (adjusted OR, 0.40 [CI, 0.18 to 0.88]) (26); another study found a well-ventilated office to be associated with a non–statistically significant decreased risk (adjusted OR, 0.32 [CI, 0.09 to 1.15]) (58). One study attempted to assess physical aspects of the hospital ward and risk for SARS-1 infection in HCWs, but only evaluated 4 wards, with many confounding factors (35).
HCW Health.
Two studies found no association between presence of comorbid conditions in HCWs and SARS-CoV-1 infection risk (60, 66). One study found having an upper respiratory infection in the past 6 months to be associated with decreased risk for SARS-CoV-1 infection (62). Another study found an HCW history of diabetes to be associated with increased univariate risk for infection, but it was not an independent predictor (58).
Infection Prevention and Control Factors.
The most consistent and robust evidence on PPE measures was on the association between use of masks and decreased infection risk (Table 2) (26, 41, 49, 50, 52, 56–58, 60, 65, 66, 72, 78). Four studies found N95 respirators to be associated with decreased risk versus surgical masks in unadjusted analyses (23, 49, 50, 60). Evidence was inconsistent on the effectiveness of multiple masks versus a single mask (26, 49). Most studies found an association between use of gloves (49, 50, 56, 58, 60, 65, 66, 72, 78), gowns (41, 50, 52, 56, 60, 65, 66, 78), eye protection (23, 26, 41, 49, 52, 58, 60, 78), or shoe covers (26, 78) and decreased risk for HCW infections (Table 3). In some studies, individual PPE measures were not included in multivariate models, but information on the degree of correlation between PPE measures was lacking. When evaluated as “inconsistent use of more than one type of PPE,” 1 study found a strong, independent association with increased risk for HCW infection (adjusted OR, 5.06 [CI, 5.06 to 598.92]) (41). Studies also found full PPE use (gloves, mask, gown, and eye protection) to be associated with reduced infection risk versus partial PPE (33, 56, 65, 78); some studies found a dose–response relationship between more frequent or consistent PPE use and decreased risk (26, 33, 41, 78). Handwashing was associated with decreased risk for SARS-CoV-1 infection in most studies (41, 52, 56, 57, 65, 66, 72), but there was no association in others (26, 56), and handwashing was not included in some multivariate models (26, 52). Nasal washing was not independently associated with decreased risk for infection in HCWs in 3 studies (26, 49, 52). No study evaluated the association between reuse of PPE and infection risk. One study found perceived inadequacy of PPE supplies to be associated with increased risk for HCW infections (41). Infection control training and education were consistently associated with decreased infection risk, though this finding was not always retained in multivariate models (Table 3) (26, 41, 49, 57, 58).
MERS-CoV
One retrospective cohort study of 283 HCWs at a Saudi Arabian hospital found participation in MERS-CoV training to be associated with decreased risk for MERS-CoV seropositivity (adjusted RR, 0.33 [CI, 0.12 to 0.90]) (Appendix Table 7) (19). Cases occurred almost exclusively among HCWs with close contact with patients with MERS. Always using an N95 respirator was associated with a non–statistically significant decreased risk compared with some or no use (adjusted RR, 0.44 [CI, 0.15 to 1.24]). Past or current smoking was associated with a non–statistically significant increased risk for infection.
Another study evaluated risk factors for MERS-CoV seropositivity in 737 HCWs who had direct contact with a patient with MERS in 31 hospitals in South Korea (37), but only reported 2 cases in HCWs (both of whom had not used appropriate PPE).
Key Question 3: Risk Factors for Transmission of Coronavirus Infection From HCWs
No study evaluated risk factors for transmission of coronavirus infections from HCWs to household or other close contacts. Four studies (24, 31, 42, 73) that did not evaluate risk factors for HCW transmission but compared SARS-CoV-1 transmission incidence from HCWs versus non-HCWs to household contacts are described in the full report (10).
Discussion
This rapid, living review summarizes the evidence on the burden of and risk factors for HCW coronavirus infections. Health care workers account for a significant proportion of infections in these outbreaks. Exposed HCWs may experience a high incidence of infections, particularly for unprotected and repeated exposures, though they appear to experience less severe illness and mortality than non-HCWs, possibly related to younger age and fewer comorbid conditions. Evidence that depression, anxiety, and psychological distress are common in HCWs in the COVID-19 outbreak is consistent with findings from the SARS-1 outbreak (83–90). Evidence on risk factors for coronavirus infections in HCWs is primarily available for SARS-CoV-1, with the strongest evidence indicating an association between PPE use versus nonuse and decreased risk. The association was most consistent for masks but was also observed for gloves, gowns, and eye protection, as well as handwashing. There was evidence that more consistent and full use of recommended PPE measures was associated with decreased risk for infection, suggesting a dose–response relationship, and evidence that N95 respirators might be associated with decreased risk for infection versus surgical masks. Evidence also indicated an association between certain exposures (such as involvement in intubations, direct contact with infected patients, or contact with bodily secretions) and increased infection risk. Education and training in infection control measures were consistently associated with decreased risk for HCW infections.
Our findings are generally consistent with prior reviews on risk factors for respiratory infections in HCWs, including PPE use (91–96). It differs from prior reviews by including recent evidence on risk factors (including those related to SARS-CoV-2 infections), focusing on coronavirus infections, excluding surrogate markers for transmission risk, evaluating a broader array of potential risk factors, and including a more comprehensive set of relevant studies. In addition, we implemented living review processes to incorporate new evidence on an ongoing basis.
The evidence base has important limitations. The evidence on SARS-CoV-2 infections in HCWs is sparse and has methodological limitations. Many studies on the burden of SARS-CoV-2 infections are case series and epidemiologic evaluations; evaluations of clinical cohorts of exposed HCWs are lacking. Studies on SARS-CoV-2 infections in HCWs that reported mental health or sleep outcomes used a cross-sectional design, did not control for baseline status, and did not include a non-HCW comparison group. Almost all studies on risk factors were retrospective and susceptible to recall bias with regard to PPE use and other factors. Some risk factor studies did not control for confounders, and those that did had limited ability to control for exposure intensity and frequency. Few studies that analyzed risk factors in multivariate models addressed collinearity (97), complicating interpretation for potentially correlated risk factors (for example, use of different types of PPE). Case–control studies did not match cases and controls on such factors as age, sex, or HCW role. Applicability of evidence on SARS-CoV-1 and MERS-CoV infections to SARS-CoV-2 is uncertain, owing to decreased transmission propensity, greater illness severity, or variability in affected populations. Most evidence on SARS-CoV-2 in HCWs is from China; studies from other settings, including those with decreased availability or use of infection prevention and control measures, are needed.
The review process had limitations, in particular the use of streamlined rapid review methods for searching and selecting studies. We did not assess study quality by using a formal instrument, though key methodological limitations were highlighted. We included non–peer-reviewed studies on SARS-CoV-2 infection in HCWs, given the lack of peer-reviewed literature, which may reduce data quality. Meta-analysis was not attempted owing to study limitations and heterogeneity in study designs, comparisons, and analyses.
Studies are needed to better understand the proportion of exposed HCWs who are infected with SARS-CoV-2 and associated outcomes, including economic effects; ability to work; social effects (for example, need for child care); and effects on family members and other close contacts, including transmission. Studies evaluating mental health and other outcomes should control for baseline status, include non-HCW controls, and incorporate longitudinal follow-up. Recovered HCWs require evaluation to understand outcomes over time (such as after return to work). For assessing SARS-CoV-2 infection risk factors, studies that prospectively measure exposures, PPE use, and other factors would increase measurement accuracy, reduce recall bias, and enable analyses that minimize confounding. Multivariate analyses of risk factors should account for potential collinearity. Given current limitations related to PPE supply, research on effects of PPE reuse is a priority (98). Studies are needed on the association between administrative factors, environmental factors, and HCW health and risk for HCW infections.
In conclusion, HCWs experience significant burdens from coronavirus infections, including SARS-CoV-2. Use of PPE and infection control training are associated with decreased infection risk and certain exposures are associated with increased risk. Research is urgently needed on optimal methods for reducing HCW risk for SARS-CoV-2 infections.
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Annals of Internal Medicine
Volume 173 • Number 2 • 21 July 2020
Pages: 120 - 136
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Published online: 5 May 2020
Published in issue: 21 July 2020
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Epidemiology of and Risk Factors for Coronavirus Infection in Health Care Workers: A Living Rapid Review. Ann Intern Med.2020;173:120-136. [Epub 5 May 2020]. doi:10.7326/M20-1632
Epidemiology of and Risk Factors for Coronavirus Infection in Health Care Workers: A Living Rapid Review. Ann Intern Med.2020;173:120-136. [Epub 5 May 2020]. doi:10.7326/M20-1632
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N95 respirators vs medical masks
In the discussion the authors stated: "[...] evidence that N95 respirators might be associated with decreased risk for infection versus surgical masks."This sentence could have major consequences at a time when PPE shortages are a great concern.
Please consider: Ng K et al: Covid-19 and the risk for health care workers Annals of Internal Medicine; Radonovich LJ et al, JAMA 2019, Bartoszko JL et al.: Medical masks vs N95 respirators for preventing COVID-19 in healthcare workers. Influenza and other respiratory viruses.
Disclosures:
Any conflict of interest
COVID Isolation - To the Editor, Annals of Internal Medicine
Comment: To the editor, We are writing to endorse and extend the findings of Chou, R. et al in Epidemiology of and Risk Factors for Coronavirus Infection in Healthcare Workers, A Living Rapid Review, Annals.org, 5 May 2020.
The WHO, CDC and the European Centre for Disease Prevention and Control have been inconsistent in their recommendations for health worker protection from aerosolized SARS-CoV-2. (1) There is a lack of clarity concerning when to use droplet precautions or airborne precautions. The CDC initially specified airborne but then changed to droplet precautions. In fact, the difference between the two is often arbitrarily set as protection from infections associated with aerosol droplets of less or greater than than 5 microns.
For influenza, droplet precautions are specified but there is a lower rate of infection when health care workers wear an N95 mask compared to a surgical mask. (2) Viral particles have been associated with droplets and droplet nuclei of all sizes. We endorse the use of N95 masks and high flow negative pressure rooms for all patients with COVID-19. Some have speculated that the CDC may have changed their recommendations because there was a shortage of N95 masks and it was impractical for facilities to create an adequate supply of negative pressure rooms.
Now that the supply of these masks is improving, recommendations should change. We, and others, began having staff wear a surgical mask over the N95 so that the surgical mask could be discarded and the N95 could be reused. We at Holy Name Medical Center in Teaneck New Jersey were confronted by an overwhelming number of patients with COVID-19 including approximately 25 admissions per day and a maximum daily census of 245. Fortunately our Facilities Team was able to retrofit rooms and create capacity for over 276 patients to be managed in negative pressure rooms. This was accomplished by removing a window from each room and replacing it with a panel and a 10 inch flexible air duct connected to high-volume exhaust fans with HEPA filters on the roof. In addition, five modular ICUs were constructed in a conference hall and other space.
These ICUs each accommodated approximately 20 beds and had negative pressure. The ventilators, monitors, IV pumps and computers all resided outside of the ICUs with tubing and cables entering through a small sealed port. In addition we developed a second level of negative pressure using a device we called an “isopod” to further protect the staff especially during procedures and transport. Considering that COVID-19 is a potentially very lethal infection with no substantially effective therapy, the infecting dose may be as low as 500 viral particles carried on the smallest droplets and remaining suspended for long periods over significant distances with prolonged exposure for caregivers; the only sensical level of protection is airborne isolation. Fortunately, this can be achieved under most circumstances as described above.
We are ready to share the details of this build out with any who are interested.
Thomas Birch MD, Ravit Barkama MD MPH, Steve Mosser, Suraj Saggar DO
(1) Bahl,P et al. Airborne or Droplet Precautions for Health Workers Treating Coronavirus Disease 2019? J. Inf Dis, jiaa189, 16Apr2020
(2) MacIntyre, CR et al. The Efficacy of Medical Masks and Respirators against Respiratory Infection in Healthcare Workers. J. Influenza Other Respi Viruses 2017;11:511-7
Update Alert: Epidemiology of and Risk Factors for Coronavirus Infection in Health Care Workers
This is the first monthly update alert for a living review on the epidemiology of and risk factors for coronavirus infections in health care workers (HCWs) (1). Searches were updated from 24 April 2020 to 24 May 2020, using the same search strategies as the original review, and we identified 1125 citations. Applying the same inclusion criteria, we identified 37 additional studies for this update (2–33-34–38). All evaluated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, except for 2 studies, identified from reference lists, on Middle East Respiratory Syndrome coronavirus (MERS-CoV) infection (12, 24).
The original rapid review included 15 studies on the burden of SARS-CoV-2 infection
(Supplement Tables 1 and 2; all supplemental tables are available at Annals.org).
Twenty-nine new studies (N = 573 352) were added: 11 cohort (2, 6, 8, 11, 14, 18, 21–23, 32, 35), 17 case–control (3, 5, 7, 13, 17, 19, 20, 25–31, 33, 36, 37), and 1 case series (15). Four studies were conducted in China, 4 in the United States, 18 in Europe, and 2 in Iran, and 1 study was conducted in both the United States and United Kingdom. Fourteen studies had not been peer-reviewed (2, 6, 9, 16, 17, 21–23, 28–30, 34, 35, 38). Other study limitations were inadequate information on clinical presentation or selection for testing; there was also variability in populations, clinical setting, and methods for diagnosing SARS-CoV-2 infection. In the new studies, the proportion of HCWs with coronavirus disease 2019 (COVID-19) ranged from 1.1% to 23.3% (7 studies) (2, 3, 8, 14, 35–37); SARS-CoV-2 infection (not necessarily meeting COVID-19 criteria) ranged from 0.4% to 49.6% (19 studies) (5–7, 11, 15, 17–19, 21–23, 25–29, 31–33), and SARS-CoV-2 antibodies ranged from 1.6% to 24.4% (3 studies) (13, 28, 30). As in the original rapid review, SARS-CoV-2 infection seemed to be somewhat less severe in HCWs than in non-HCWs (5, 6, 15, 16), with a case-fatality rate of 0% and 1.2% in 2 studies (15, 16). One analysis of all cases in Italy estimated slightly higher mortality due to COVID-19 in physicians and dentists (0.046%) than in the general population (0.039%), due to increased infection incidence (20). Eight new studies were consistent with previous findings that HCWs in areas affected by COVID-19 report high levels of depression, anxiety, and psychological distress (Supplement Table 2) (4, 9, 10, 16, 26, 34, 36, 38).
Like prior studies, the new studies used a cross-sectional design, did not control for baseline symptoms, did not have a non-HCW control group, and did not control for work exposures.
Ten new studies (N = 149 240) evaluated risk factors for SARS-CoV-2 infection in HCWs (Supplement Table 3) (2, 6, 13, 14, 17, 22, 28, 33, 35, 37). All were susceptible to recall bias and did not adjust for confounders. The most frequently addressed risk factors were age, sex, hospital department, and HCW role or position. Results were consistent with the original rapid review (Supplement Tables 6 to 10).
Two small studies (n = 40 and 9) identified through reference list review addressed MERS-CoV infections in HCWs (Supplement Tables 1 and 5) (12, 24). Results did not change the conclusions of the original rapid review.
Supplemental material can be found here: https://www.acpjournals.org/doi/10.7326/L20-0768
References
Disclosures:
Go to https://doi.org/10.7326/L20-0768 for Disclosures
Update Alert 2: Epidemiology of and Risk Factors for Coronavirus Infection in Health Care Workers
This is the second monthly update alert for a living rapid review on the epidemiology of and risk factors for coronavirus infection in health care workers (HCWs) (1). Searches were updated from 24 May 2020 to 24 June 2020, using the same search strategies as the original review. The update searches identified 2087 citations. Due to the high volume of literature and to focus on higher-quality evidence, we modified selection criteria for this and future updates by restricting inclusion to peer-reviewed studies, studies on incidence or outcomes of HCW infections with clearly defined inception cohorts, and studies on mental health or quality of life that controlled for baseline symptoms. Other inclusion criteria were unchanged. Four studies, all on SARS-CoV-2 infection, were added for this update (2–5).
The original rapid review included 15 studies on the burden of SARS-CoV-2 infection; 29 studies were added for the first monthly update (Supplement Tables 1 and 2; all supplemental tables are available at Annals.org). Four cohort studies were added for this update (2–5). Of the new studies, 1 was conducted in the United States (2), 1 in Austria (3), 1 in China (5), and 1 was multinational (4). There was also variability across studies in SARS-CoV-2 exposures and criteria for diagnosing HCW infections; 2 studies (2, 3) did not provide demographic or clinical information. In the new studies, the proportion of HCWs with COVID-19 was 3.1% and 6.8% in 2 studies (2, 4) and the proportion with SARS-CoV-2 infection (not necessarily meeting criteria for COVID-19) was 19.2% in 1 study (3); these estimates were within previously described ranges. One new prospective study found that measures of mood, anxiety, and depression worsened in HCWs in China after compared with before the pandemic (5). This builds on prior studies that found that HCWs in areas affected by COVID-19 report high levels of depression, anxiety, and psychological distress, but the studies did not control for baseline symptoms. Like prior studies, the new study did not have a non-HCW control group or control for work exposures. No new study reported the severity of SARS-CoV-2 infections in HCWs.
Two new studies (n = 1744) evaluated risk factors for SARS-CoV-2 infection in HCWs (Supplement Table 3) (3, 4). One new study evaluated HCWs involved in tracheal intubation of patients who were enrolled in a registry (4). An important limitation of this study was that infections included patients with laboratory-confirmed COVID-19 infection, as well as those with symptoms but no laboratory diagnosis. The other new study reported a very imprecise estimate of risk for SARS-CoV-2 infection in nurses versus physicians and did not adjust for confounders (3). Results for risk factors updated with these studies were judged to be consistent with the original rapid review and prior update (Supplement Tables 6 to 10).
This article was published at Annals.org on 14 July 2020
REFERENCES
1. Chou R, Dana T, Buckley DI, et al. Epidemiology of and risk factors for coronavirus infection in health care workers. Ann Intern Med. 2020. [PMID: 32369541] doi:10.7326/M20-1632
2. Baker MA, Rhee C, Fiumara K, et al. COVID-19 infections among HCWs exposed to a patient with a delayed diagnosis of COVID-19. Infect Control Hosp Epidemiol. 2020:1-2. [PMID: 32456720] doi:10.1017/ice.2020.256
3. Buchtele N, Rabitsch W, Knaus HA, et al. Containment of a traceable COVID-19 outbreak among healthcare workers at a hematopoietic stem cell transplantation unit [Letter]. Bone Marrow Transplant. 2020;55:1491-1492. [PMID: 32483288] doi:10.1038/s41409-020-0958-6
4. El-Boghdadly K, Wong DJN, Owen R, et al. Risks to healthcRoger are workers following tracheal intubation of patients with COVID-19: a prospective international multicentre cohort study. Anaesthesia. 2020. [PMID: 32516833] doi:10.1111/anae.15170
5. Li W, Frank E, Zhao Z, et al. Mental health of young physicians in china during the novel coronavirus disease 2019 outbreak. JAMA Netw Open. 2020;3:e2010705. [PMID: 32478846] doi:10.1001/jamanetworkopen.2020.10705
Disclosures:
Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M20-4806.
Update Alert 3: Epidemiology of and Risk Factors for Coronavirus Infection in Health Care Workers
This is the third monthly update alert for a living rapid review on the epidemiology of and risk factors for coronavirus infection in health care workers (HCWs) (1). Searches were updated from 25 June 2020 to 24 July 2020, using the same search strategies as the original review. The update searches identified 2010 citations. We applied the same inclusion criteria used for the prior update, with previously described protocol modifications to focus on higher-quality evidence (2). Eight studies, all on SARS-CoV-2 infection, were added for this update (3–10).
The original rapid review included 15 studies on the burden of SARS-CoV-2 infection (1); 34 studies were added in prior updates (2, 11) ( Supplement ). Three cohort studies (7–9) and 2 cross-sectional studies (3, 6) on the burden of SARS-CoV-2 infection were added for this update. Of the new studies, 1 was conducted in the United States (3) and the others in Europe: Belgium (8), Italy (6), Germany (9), and Greece (7). The proportion of HCWs with COVID-19 was 1.9% in 1 study (3); the proportion with SARS-CoV-2 infection ranged from 2.2% to 12.6% in 3 studies (6, 8, 9); and the proportion with SARS-CoV-2 seropositivity was 7.6% in 1 study (10). Among HCWs with SARS-CoV-2 infection, the proportion hospitalized ranged from 0% to 1.7% in 3 studies (n = 5839), with no deaths (6–8). All estimates were within previously described ranges.
The original rapid review included 31 studies on risk factors for SARS-CoV-2 infection (1); 12 were added in prior updates (2, 11). For this update, 7 new studies (n = 8762) evaluated risk factors for SARS-CoV-2 infection in HCWs ( Supplement ) (4–10). One case–control study found performing endotracheal intubation and never using personal protective equipment was associated with increased risk for SARS-CoV-2 infection in a multivariate analysis (4). Use of masks, caps, gowns, shoe covers, gloves, or face shields were associated with decreased risk in univariate analysis but were not retained in the multivariate model. Limitations included potential recall bias, failure to address potential collinearity, and limited measurement and control of exposures. A prospective cohort study found high-risk exposure associated with increased risk for a COVID-19 diagnosis versus moderate- or low-risk exposure in an adjusSupppted analysis; exposure was categorized using an unvalidated method, on the basis of mask use by the infected patient and personal protective equipment use by the HCW (7). Four studies (4, 7, 9, 10) found no association between sex and risk for SARS-CoV-2 infection, and 5 studies (5, 6, 8–10) reported inconsistent findings for the risk for SARS-CoV-2 infection in nurses versus physicians. Results for risk factors updated with these studies were judged to be consistent with the original rapid review and prior update ( Supplement ).
This article was published at Annals.org on 3 August 2020
References
1. Chou R, Dana T, Buckley DI, et al. Epidemiology of and risk factors for coronavirus infection in health care workers: a living rapid review. Ann Intern Med. 2020;173:120-136. [PMID: 32369541] doi:10.7326/M20-1632
2. Chou R, Dana T, Buckley DI, et al. Update alert 2: epidemiology of and risk factors for coronavirus infection in health care workers [Letter]. Ann Intern Med. 2020. [PMID: 32663033] doi:10.7326/M20-4806
3. Bays DJ, Nguyen MH, Cohen SH, et al. Investigation of nosocomial SARS-CoV-2 transmission from two patients to health care workers identifies close contact but not airborne transmission events. Infect Control Hosp Epidemiol. 2020:1-22. [PMID: 32618530] doi:10.1017/ice.2020.321
4. Chatterjee P, Anand T, Singh KJ, et al. Healthcare workers & SARS-CoV-2 infection in India: A case-control investigation in the time of COVID-19. Indian J Med Res. 2020;151:459-467. [PMID: 32611916] doi:10.4103/ijmr.IJMR_2234_20
5. García IS, López MJMA, Vicente AS, et al. SARS-CoV-2 infection among healthcare workers in a hospital in Madrid, Spain. J Hosp Infect. 2020. [PMID: 32702465] doi:10.1016/j.jhin.2020.07.020
6. Lahner E, Dilaghi E, Prestigiacomo C, et al. Prevalence of SARS-CoV-2 infection in health workers (HWs) and diagnostic test performance: the experience of a teaching hospital in central italy. Int J Environ Res Public Health. 2020;17. [PMID: 32575505] doi:10.3390/ijerph17124417
7. Maltezou HC, Dedoukou X, Tseroni M, et al. SARS-CoV-2 infection in healthcare personnel with high-risk occupational exposure: evaluation of seven-day exclusion from work policy. Clin Infect Dis. 2020. [PMID: 32594160] doi:10.1093/cid/ciaa888
8. Martin C, Montesinos I, Dauby N, et al. Dynamic of SARS-CoV-2 RT-PCR positivity and seroprevalence among high-risk health care workers and hospital staff. J Hosp Infect. 2020. [PMID: 32593608] doi:10.1016/j.jhin.2020.06.028
9. Schmidt SB, Grüter L, Boltzmann M, et al. Prevalence of serum IgG antibodies against SARS-CoV-2 among clinic staff. PLoS One. 2020;15:e0235417. [PMID: 32584894] doi:10.1371/journal.pone.0235417
10. Stubblefield WB, Talbot HK, Feldstein L, et al; Influenza Vaccine Effectiveness in the Critically Ill (IVY) Investigators. Seroprevalence of SARS-CoV-2 among frontline healthcare personnel during the first month of caring for COVID-19 patients - Nashville, Tennessee. Clin Infect Dis. 2020. [PMID: 32628750] doi:10.1093/cid/ciaa936
11. Chou R, Dana T, Buckley DI, et al. Update alert: epidemiology of and risk factors for coronavirus infection in health care workers [Letter]. Ann Intern Med. 2020;173:W46-W47. [PMID: 32515983] doi:10.7326/L20-0768
Disclosures:
Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M20-4806.
Update Alert 4: Epidemiology of and Risk Factors for Coronavirus Infection in Health Care Workers
This is the fourth monthly update alert for a living rapid review on the epidemiology of and risk factors for coronavirus infection in health care workers (HCWs) (1). Searches were updated from 25 July to 24 August 2020 using the same search strategies as the original review. The update searches identified 2494 citations. We applied the same inclusion criteria used for the prior update, with previously described protocol modifications to focus on higher-quality evidence (2). Seventeen studies (3–19) on burden of and risk factors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection were added for this update.
The original rapid review included 15 studies on the burden of SARS-CoV-2 infection (1); 42 studies were added in prior updates (2, 20, 21) (Supplement Tables 1 and 2). For this update, 10 cohort studies (4, 5, 7, 8, 11, 13, 15–18), 5 cross-sectional studies (3, 9, 10, 12, 14), and 1 case–control study (6) on the burden of SARS-CoV-2 infection were added. Of the new studies, 3 were done in the United States (9, 10, 13); 3 in Italy (3, 15, 16); 2 in the United Kingdom (7, 8); 2 in China (18, 19); and 1 each in Belgium (5), Germany (12), Spain (14), Turkey (6), and Egypt (11). The country was not reported in 1 study (4).
As in the prior updates and review, estimates of SARS-CoV-2 infection in HCWs varied (Supplement Table 1). Among the new studies, 9 reported rates of SARS-CoV-2 seropositivity that ranged from 1.6% to 31.6% (3, 5, 7, 9, 10, 12–14, 16), 6 reported rates of SARS-CoV-2 infection (based on polymerase chain reaction positivity) of 0.4% to 23.5% (4, 14, 15, 17–19), and 2 studies reported rates of either SARS-CoV-2 seropositivity or infection (polymerase chain reaction positive) of 12.2% and 43.5% (8, 11). Factors contributing to the variability in estimates likely include differences in locale, SARS-CoV-2 outbreak severity, presence and severity of HCW symptoms, and exposure extent. Limitations of the studies included variability in participation rates and failure to provide information about the severity or clinical outcomes of SARS-CoV-2 infections.
The original rapid review included 31 studies on risk factors for SARS-CoV-2 infection (1); 19 studies were added in prior updates (2, 20). For this update, 15 new studies (n = 51 597) evaluated risk factors (Supplement Table 3) (3, 5–18). Study limitations include limited measurement and control of exposures, potential recall bias, and failure to address potential collinearity. Ten studies (3, 6, 8, 10–13, 15–17) indicated no association between sex and risk for SARS-CoV-2 infection, and 13 studies (3, 5, 6, 8–11, 13–18) reported inconsistent findings for differences in risk between nurses and physicians. One study found that mask use (FFP2, FFP3, or surgical mask) was associated with increased risk for SARS-CoV-2 infection versus no mask use. Although FFP2 and FFP3 mask use was associated with increased risk for SARS-CoV-2 infection versus surgical mask use, the analysis only adjusted for age (15). Another study found that improper use of personal protective equipment while caring for patients with suspected or confirmed coronavirus disease 2019 and break room exposure to another HCW without wearing a mask were associated with increased risk for HCW infection, after adjustment for other exposures (6). Results for risk factors updated with these studies were judged to be consistent with the original prior update (Supplement Tables 4 to 7).
This article was published at Annals.org on 11 September 2020
References
1. Chou R, Dana T, Buckley DI, et al. Epidemiology of and risk factors for coronavirus infection in health care workers: a living rapid review. Ann Intern Med. 2020;173:120-136. [PMID: 32369541] doi:10.7326/M20-1632
2. Chou R, Dana T, Buckley DI, et al. Update alert 2: epidemiology of and risk factors for coronavirus infection in health care workers [Letter]. Ann Intern Med. 2020. [PMID: 32663033] doi:10.7326/M20-4806
3. Amendola A, Tanzi E, Folgori L, et al. Low seroprevalence of SARS-CoV-2 infection among healthcare workers of the largest children hospital in Milan during the pandemic wave. Infect Control Hosp Epidemiol. 2020:1-6. [PMID: 32758311] doi:10.1017/ice.2020.401
4. Blain H, Rolland Y, Tuaillon E, et al. Efficacy of a test–retest strategy in residents and health care personnel of a nursing home facing a COVID-19 outbreak. J Am Med Dir Assoc. 2020;21:933-936. [PMID: 32674822] doi:10.1016/j.jamda.2020.06.013
5. Blairon L, Mokrane S, Wilmet A, et al. Large-scale, molecular and serological SARS-CoV-2 screening of healthcare workers in a 4-site public hospital in Belgium after COVID-19 outbreak. J Infect. 2020. [PMID: 32739485] doi:10.1016/j.jinf.2020.07.033
6. Çelebi G, Pişkin N, Çelik Bekleviç A, et al. Specific risk factors for SARS-CoV-2 transmission among health care workers in a university hospital. Am J Infect Control. 2020. [PMID: 32771498] doi:10.1016/j.ajic.2020.07.039
7. Grant JJ, Wilmore SMS, McCann NS, et al. Seroprevalence of SARS-CoV-2 antibodies in healthcare workers at a London NHS Trust. Infect Control Hosp Epidemiol. 2020. [PMID: 32746953] doi:10.1017/ice.2020.402
8. Houlihan CF, Vora N, Byrne T, et al. Pandemic peak SARS-CoV-2 infection and seroconversion rates in London frontline health-care workers. Lancet. 2020;396:e6-e7. [PMID: 32653078] doi:10.1016/S0140-6736(20)31484-7
9. Hunter BR, Dbeibo L, Weaver CS, et al. Seroprevalence of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) antibodies among healthcare workers with differing levels of coronavirus disease 2019 (COVID-19) patient exposure. Infect Control Hosp Epidemiol. 2020. [PMID: 32741406] doi:10.1017/ice.2020.390
10. Jeremias A, Nguyen J, Levine J, et al. Prevalence of SARS-CoV-2 infection among health care workers in a tertiary community hospital. JAMA Intern Med. 2020. [PMID: 32780100] doi:10.1001/jamainternmed.2020.4214
11. Kassem AM, Talaat H, Shawky S, et al. SARS-CoV-2 infection among healthcare workers of a gastroenterological service in a tertiary care facility. Arab J Gastroenterol. 2020. [PMID: 32732168] doi:10.1016/j.ajg.2020.07.005
12. Lackermair K, William F, Grzanna N, et al. Infection with SARS-CoV-2 in primary care health care workers assessed by antibody testing. Fam Pract. 2020. [PMID: 32766704] doi:10.1093/fampra/cmaa078
13. Moscola J, Sembajwe G, Jarrett M, et al. Prevalence of SARS-CoV-2 antibodies in health care personnel in the New York City area. JAMA. 2020;324:893-895. [PMID: 32780804] doi:10.1001/jama.2020.14765
14. Olalla J, Correa AM, Martín-Escalante MD, et al. Search for asymptomatic carriers of SARS-CoV-2 in healthcare workers during the pandemic: a Spanish experience. QJM. 2020. [PMID: 32777050] doi:10.1093/qjmed/hcaa238
15. Piapan L, De Michieli P, Ronchese F, et al. COVID-19 outbreak in healthcare workers in Trieste hospitals (North–Eastern Italy). J Hosp Infect. 2020. [PMID: 32805309] doi:10.1016/j.jhin.2020.08.012
16. Sotgiu G, Barassi A, Miozzo M, et al. SARS-CoV-2 specific serological pattern in healthcare workers of an Italian COVID-19 forefront hospital. BMC Pulm Med. 2020;20:203. [PMID: 32727446] doi:10.1186/s12890-020-01237-0
17. Villanueva AMG, Lazaro J, Sayo AR, et al. COVID-19 screening for healthcare workers in a tertiary infectious diseases referral hospital in Manila, the Philippines. Am J Trop Med Hyg. 2020;103:1211-1214. [PMID: 32729461] doi:10.4269/ajtmh.20-0715
18. Zhang GQ, Pan HQ, Hu XX, et al. The role of isolation rooms, facemasks and intensified hand hygiene in the prevention of nosocomial COVID-19 transmission in a pulmonary clinical setting. Infect Dis Poverty. 2020;9:104. [PMID: 32703281] doi:10.1186/s40249-020-00725-z
19. Zhao D, Wang M, Wang M, et al. Asymptomatic infection by SARS-CoV-2 in healthcare workers: a study in a large teaching hospital in Wuhan, China. Int J Infect Dis. 2020;99:219-225. [PMID: 32758693] doi:10.1016/j.ijid.2020.07.082
20. Chou R, Dana T, Buckley DI, et al. Update alert: epidemiology of and risk factors for coronavirus infection in health care workers. Ann Intern Med. 2020;173:W46-W47. [PMID: 32515983] doi:10.7326/L20-0768
21. Chou R, Dana T, Buckley DI, et al. Update alert 3: epidemiology of and risk factors for coronavirus infection in health care workers. Ann Intern Med. 2020. [PMID: 32744870] doi:10.7326/L20-1005
Disclosures:
Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=L20-1134.
Update Alert 5: Epidemiology of and Risk Factors for Coronavirus Infection in Health Care Workers
This is the fifth monthly update alert for a living rapid review on the epidemiology of and risk factors for coronavirus infection in health care workers (HCWs) (1). Searches were updated from August 25, 2020 to September 24, 2020, using the same search strategies as the original review. The update searches identified 1,987 citations. We applied the same inclusion criteria used for the prior update, with previously described protocol modifications to focus on higher quality evidence (2). Ten studies (3-12) on burden of and risk factors for SARS-CoV-2 infection were added for this update.
The original rapid review included 15 studies on the burden of SARS-CoV-2 infection (1); 52 studies were added in prior updates (2, 13-15) (Appendix Tables 1 and 2). For this update, three cohort studies (3, 4, 9) and five cross-sectional studies (5-7, 11, 12) were added. Studies were conducted in Belgium (11), Brazil (6), China (12), France (4), Italy (7), Qatar (3) the United Kingdom (9), and the United States (5).
In the original review and prior updates, the incidence of SARS-CoV-2 infection (PCR-positive) ranged from 0.4% to 49.6% and the prevalence of SARS-CoV-2 seropositivity ranged from 1.6% to 31.6%; the wide ranges in estimates were likely related to differences in settings, exposures, rates of community transmission, symptom status, use of infection control measures, and other factors. Consistent with prior findings, estimates from new studies of SARS-CoV-2 infection in HCWs varied and were within previously reported ranges (Appendix Table 1). Five studies reported rates of SARS-CoV-2 infection based on PCR positivity that ranged from 1.7% to 43.4% (3-7, 9). One study reported a seropositive rate of 6.4% (11) and two studies reported infection rates of 3.4% (12) and 3.5% (7) based on a combination of PCR, seropositivity and/or CT scan findings. Limitations of the studies included failure to provide information regarding the severity or clinical outcomes of SARS-CoV-2 infections in HCWs and, in some studies, small sample sizes or unclear participation rates.
One new study conducted in China at the beginning of the SARS-CoV-2 outbreak was consistent with prior studies in finding that HCWs had higher levels of depression, anxiety and insomnia relative to the general population (10). However, the study did not control for baseline symptoms.
The original rapid review included 34 studies on risk factors for coronavirus infections (3 studies on risk factors for SARS-CoV-2 infection, 29 studies on SARS-CoV-1 infection, and 2 studies on MERS-CoV infection) (1); 36 studies (34 studies on SARS-CoV-2, 0 studies on SARS-CoV-1, and 2 studies on MERS-CoV) were added in prior updates (2, 13, 15). For this update, five new studies (N=5,436) evaluated risk factors for SARS-CoV-2 infection in HCWs (Appendix Table 3) (6-9, 12). Limitations of the studies include limited measurement of exposures, potential recall bias, no control of confounders, and imprecise estimates. Four studies (7-9, 12) indicated no association between sex and risk of SARS-CoV-2 infection and two studies (6, 7) reported inconsistent findings for the risk of SARS-CoV-2 infection in nurses versus physicians. One small case-control study that did not control for confounders found providing direct patient care or performing an aerosol-generating procedure on a patient with unknown COVID-19 status was associated with an increased risk of HCW infection (8). Most estimates for PPE were imprecise, though use of a face shield or goggles was associated with reduced risk of SARS-CoV-2 infection. One study found infection control education associated with decreased risk of SARS-CoV-2 infection (12) and one study reported a very imprecise estimate for infection control training (7). Overall, results for risk factors updated with these studies were judged to be consistent with the original review and prior updates (Appendix Tables 4-8).
References
Disclosures:
Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=L20-1227.
Update Alert 6: Epidemiology of and Risk Factors for Coronavirus Infection in Health Care Workers
This is the sixth monthly update alert for a living rapid review on the epidemiology of and risk factors for coronavirus infection in health care workers (HCWs) (1). Searches were updated from September 25, 2020 to October 24, 2020, using the same search strategies as the original review. The update searches identified 1,552 citations. We applied the same inclusion criteria used for the prior update, with previously described protocol modifications (2) to focus on higher quality evidence. Eight studies (3-10) on burden of and risk factors for SARS-CoV-2 infection were added for this update.
The original rapid review included 15 studies on the burden of SARS-CoV-2 infection (1); 62 studies were added in prior updates (2, 11-14) (Appendix Tables 1 and 2). For this update, 8 cross-sectional studies (3-10) were added. Three studies were conducted in Asia (7, 9, 15), five studies in Europe (4-6, 8, 10), and one study in Oman (3).
Based on the original review and prior updates, incidence of SARS-CoV-2 infection (PCR-positive) ranged from 0.4% to 49.6% and the prevalence of SARS-CoV-2 seropositivity ranged from 1.6% to 31.6% (2, 11-14). The wide ranges in estimates were likely related to differences in settings, exposures, community transmission rates, symptom status, use of infection control measures, and other factors. Rates of SARS-CoV-2 infection based on PCR positivity, reported in four new studies, ranged from 0% to 9.9% (3, 4, 9, 10). SARS-CoV-2 seropositivity, reported in five new studies, ranged from 3.2% to 13.2% (4-6, 8, 10). Among health workers with SARS-CoV-2 infection, three studies reported hospitalization rates of 0% to 14.4% (3, 9, 10) and two studies reported that 0.7% and 10.2% had severe disease (7, 9). In two studies, mortality among health workers with SARS-CoV-2 infection was 0% and 0.7% (7, 9). Limitations of the studies included failure to adequately report HCW demographic characteristics, small sample sizes, unclear participation rates, and lack of information on clinical outcomes of SARS-CoV-2 infections.
The original rapid review included 34 studies on risk factors for coronavirus infections (3 studies on risk factors for SARS-CoV-2 infection, 29 studies on SARS-CoV-1 infection, and 2 studies on MERS-CoV infection) (1); 41 studies (39 studies on SARS-CoV-2) were added in prior updates (2, 11-14). For this update, five new studies evaluated risk factors for SARS-CoV-2 infection in HCWs (Appendix Table 3) (3-5, 8, 10). As in prior studies, three new studies found no association between sex and risk of SARS-CoV-2 infection (3, 8, 10) and four studies found no association between nurse or physician health worker role and risk of SARS-CoV-2 infection(3-5, 10). There was no new evidence for masks, other PPE or other risk factors, including infection control training and education (Appendix Tables 4-8).
References
Disclosures:
Disclosures can also be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M20-1632.
Update Alert 8: Epidemiology of and Risk Factors for Coronavirus Infection in Health Care Workers
This is the eighth update alert for a living rapid review on the epidemiology of and risk factors for coronavirus infection in health care workers (HCWs) (1). Updates on the original scope were monthly through Update Alert #7 (2), at which time the interval was switched to bimonthly for subsequent updates that focused on risk factors for coronavirus infection. Update searches were done from December 25, 2020 to February 24, 2021, using the same search strategies as the original review. The update searches identified 3,267 citations. We applied the same inclusion criteria used for prior updates, with previously described protocol modifications (3) to focus on higher quality evidence. Twenty studies on risk factors for SARS-CoV-2 infection were added for this update (Appendix Tables 1-6) (4-23).
The original rapid review included 34 studies on risk factors for coronavirus infections (3 studies on SARS-CoV-2, 29 studies on SARS-CoV-1, and 2 studies on MERS-CoV) (1); 64 studies (62 studies on SARS-CoV-2, 0 studies on SARS-CoV-1, and 2 studies on MERS-CoV) were added in prior updates (2, 3, 24-28). For this update, 10 cohort studies (5, 6, 11, 14, 17-19, 21-23) and 10 cross-sectional studies (4, 6-8, 10, 12, 13, 15, 16, 20) were added (Appendix Table 1). Fifteen studies were conducted in Europe (4 studies in Spain (4, 7, 10, 12), 2 each in Germany (8, 14), Italy (19, 23), and the UK (9, 12), and one each in Belgium (5), Denmark (21), France (22), Lithuania (20), and Norway (11)) and five were conducted in the United States (13, 15, 16, 18) or Canada (17). As with studies included in prior updates, the studies had methodological limitations including potential recall bias, low or unclear participation rates, small sample sizes, and potential collinearity. Some studies did not control for confounders; those that did report adjusted estimates were limited in their ability to control for exposures and personal protective equipment use.
Similar to prior report updates, estimates did not indicate an association between sex (17 studies (4-16, 18, 19, 22, 23)) and risk of SARS-CoV-2 infection or seropositivity. Thirteen studies (4-6, 8-13, 15, 16, 19, 23) found no consistent association between age and 14 new studies (4, 6, 7, 9-11, 13-15, 18-21, 23) found no consistent association between health worker role (nurse versus physician) and risk of SARS-CoV-2 infection, including two studies (14, 19) that reported adjusted risk estimates. Six new studies (6, 9, 13, 15, 16, 18) conducted in the United States or United Kingdom reported on the relationship between race or ethnicity and SARS-CoV-2 infection. In studies that controlled for confounders, Black (adjusted ORs 1.66 to 2.10 (6, 13, 15, 16)) and Hispanic (adjusted ORs 1.32 to 1.98 (13, 16)) HCWs were at increased risk of SARS-CoV-2 infection compared with white HCWs; one other study reported similar findings based on adjusted incidence rate ratios (2.78, 95% CI 1.78 to 4.33 for Black and 2.41, 95% CI 1.42 to 4.07) Hispanic HCWs relative to non-Hispanic white HCWs (18). The results from the new studies were generally consistent with prior updates on the association between demographic or clinical characteristics and risk of SARS-CoV-2 infection in HCWs (Appendix Table 3).
One new study found presence of IgG antibodies associated with decreased risk of SARS-CoV-2 reinfection in HCWs, based on PCR testing (adjusted incidence rate ratio for presence of anti-spike IgG 0.3, 95% CI 0.03 to 0.44 and for anti-spike and anti-nucleocapsid IgG 0.06, 95% CI 0.01 to 0.46)) (Appendix Table 3) (9). The association between SARS-CoV-2 antibody status and risk of HCW infection was not evaluated in studies included in the original review or prior updates.
Eleven new studies evaluated associations between more direct patient contact or contact with COVID-19 patients and risk of SARS-CoV-2 infection (Appendix Table 3) (6, 8, 10-12, 14-19). In five studies that controlled for potential confounders, working in a hospital unit with COVID-19 patients versus not working in a COVID-19 unit (adjusted ORs 1.50 to 2.39 (6, 15, 16)), being a frontline worker versus a non-frontline worker (adjusted OR 1.73, 95% CI 1.16 to 2.54 (18)) and direct patient contact versus no or minimal patient contact adjusted OR 2.06, 95% CI 1.63 to 2.62 (12)) were each associated with increased risk of infection.
Regarding infection control training and use, one new study found PPE training associated with decreased risk of infection versus no training, but the estimate was imprecise (adjusted OR 0.71, 95% CI 0.25-2.13; Appendix Table 4) (19). One study reported an imprecise estimate for N95 versus surgical mask and found use of eye protection (face shield and goggles) associated with decreased risk versus non-use (OR 0.55, 95% CI 0.36 to 0.84; Appendix Table 5) (13). PPE use “as recommended” was associated with reduced risk of SARS-CoV-2 infection compared with no use (adjusted OR 0.8, 95% CI 0.4 to 1.4) or unsure use (adjusted OR 0.6, 95% CI 0.6 to 0.9) (15), exposure to a known or suspected COVID-19 patient without use of PPE (adjusted OR 1.47, 95% CI 1.26 to 1.70) (6) and patient contact with partial PPE versus no contact (OR 2.5, 95% CI 0.5 to 12.2) (11) were associated with increased risk. Overall, results regarding exposures and PPE were judged to be consistent with prior updates (Appendix Tables 3-6).
References
Disclosures:
Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=L21-0143.
Update Alert 9: Epidemiology of and Risk Factors for Coronavirus Infection in Health Care Workers
This is the ninth update alert for a living rapid review on the epidemiology of and risk factors for coronavirus infection in health care workers (HCWs) (1). Updates were conducted monthly through Update Alert #7 (2), at which time the interval was switched to bimonthly. Update searches from February 25, 2020 to April 24, 2021 were conducted using the same search strategies as the original review. The update searches identified 3,518 citations. We applied the same inclusion criteria used for prior updates, with previously described protocol modifications (3) to focus on higher quality evidence and risk factors for coronavirus infections. Twenty-one studies on risk factors for SARS-CoV-2 infection were added for this update (Appendix Tables 1-6) (4-24).
The original rapid review included 34 studies on risk factors for coronavirus infections (3 studies on SARS-CoV-2, 29 studies on SARS-CoV-1, and 2 studies on MERS-CoV) (1); 84 studies (82 studies on SARS-CoV-2, 0 studies on SARS-CoV-1, and 2 studies on MERS-CoV) were added in prior updates (2, 3, 25-29). For this update, four cohort studies (9, 11, 15, 22) and 17 cross-sectional studies (4-8, 10, 12-14, 16-21, 23, 24) were added (Appendix Table 1). Eight studies were conducted in Europe (two in the United Kingdom (15, 22), two in France (7, 10), and one each in Belgium (11), Italy (9), Spain (21) and Sweden (20) and six in the United States (5, 8, 12, 16, 18, 23). The remaining studies were conducted in Egypt (17), Pakistan (4), Turkey (6), India (14), Malaysia (24), Thailand (19) and Japan (13). As in prior updates, the studies had methodological limitations including potential recall bias, low or unclear participation rates, small sample sizes, and potential collinearity. Some studies did not control for confounders; those that did report adjusted estimates had limitations with regard to being able to control for exposures and personal protective equipment use.
Similar to prior updates, new studies did not indicate an association between sex (16 studies (4-10, 12-17, 19, 21, 24)) and risk of SARS-CoV-2 infection or seropositivity. Twelve new studies (5, 9-11, 13, 14, 16, 18, 21-24) found no consistent association between age and 12 new studies (5-8, 10, 13-16, 21, 23, 24) found no consistent association between health worker role (nurse versus physician) and risk of SARS-CoV-2 infection. Consistent with prior updates, three new studies conducted in the United States or United Kingdom found Black race associated with a statistically significant increased risk of SARS-CoV-2 infection relative to white race (adjusted OR 2.83, 95% CI 1.77 to 4.51, (5) 2.1, 95% CI 1.8-2.4, (16) and 2.08, 95% CI 1.25-3.45 (22)) and Hispanic ethnicity associated with increased risk of SARS-CoV-2 infection relative to white race (adjusted OR 1.70, 1.35 to 2.13) (5). Results of new studies were generally consistent with prior updates on the association between demographic or clinical characteristics and risk of SARS-CoV-2 infection in HCWs (Appendix Table 2).
One new study found incidence of reinfection in HCWs who were seropositive at baseline was lower than the incidence of new infection in HCWs who were seronegative at baseline (incidence per 1000 participants 18.7 vs. 98.0 for any infection and 6.0 vs. 64.8 for symptomatic infections) (15). This evidence was consistent with a study included in the previous update (30) that found a decreased risk of new infection in seropositive HCWs (Appendix Table 2).
Fifteen new studies that reported on the association between exposures indicated that more direct or more prolonged contact was associated with increased risk, though some findings were mixed or imprecise (5, 6, 8-10, 12-20, 24). In three studies that reported adjusted risk estimates, two found working in a COVID-19 unit associated with increased risk of SARS-CoV-2 infection versus not working in a COVID-19 unit (5, 20) and one study found decreased risk of infection (15). Three new studies found direct contact with a COVID-19 infected co-worker of patient associated with increased risk of infection versus no or limited contact (5, 16, 20), although differences were not all statistically significant (Appendix Table 3).
One new study reported imprecise estimates for the association between training for PPE donning and doffing or implementation of PPE shortage protocols versus no training and risk of infection (Appendix Table 4) (5). Regarding mask and PPE use, one new study (15) found consistent mask use associated with lower risk of SARS-CoV-2 infection compared with inconsistent use (Appendix Table 5) and one study (5) reported no significant decrease in risk of infection with exposure to a COVID-19-infected patient while wearing PPE (Appendix Table 6). Overall, results regarding training and PPE were judged to be consistent with prior updates (Appendix Tables 4-6).
Evidence across all risk factors for SARS-CoV-2 infection in HCWs is summarized in Appendix Table 7. Despite large numbers of studies and participants, most evidence remains low or moderate certainty, due to methodological limitations, imprecision, and inconsistency. Given little change in conclusions after one year of monthly or bimonthly updates, we are extending the interval between updates to every six months.
References
Disclosures:
Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=L21-0302.
Update Alert 10: Epidemiology of and Risk Factors for Coronavirus Infection in Health Care Workers
This is the tenth update alert for a living review on the epidemiology of and risk factors for coronavirus infection in health care workers (HCWs) (1). Initial updates were monthly through Update Alert #7 (2), then bimonthly for Update Alerts #8 (3) and 9 (4), which focused on risk factors for coronavirus infection. Beginning with this update, we limited inclusion to studies that reported adjusted risk estimates, to focus on higher quality evidence, and the update interval was extended to biannually, given stable findings in prior updates. We excluded non-peer-reviewed studies, except for studies comparing mask types conducted in or after January 2021, when the delta variant emerged. Searches for this update were conducted from April 25, 2021 to October 24, 2021, using the same search strategies as the original review, and identified 8,656 citations. We applied the same inclusion criteria used for prior updates, other than described above. Twenty studies on risk factors for SARS-CoV-2 infection were added for this update (Appendix Tables 1-6) (6-25).
The original rapid review included 34 studies on risk factors for coronavirus infections (3 studies on SARS-CoV-2, 29 studies on SARS-CoV-1, and 2 studies on MERS-CoV) (1); 93 studies (91 studies on SARS-CoV-2, 0 studies on SARS-CoV-1, and 2 studies on MERS-CoV) were added in prior updates (2-5, 26-29). For this update, four cohort studies (6-9) (including one pre-print study (9)), 15 cross-sectional studies (10-24), and one case-control study (25), all on SARS-CoV-2, were added (Appendix Table 1). Ten studies were conducted in Europe and seven were conducted in North America. The others were conducted in Kuwait, Qatar, and Turkey. In 18 studies, data were collected from February to December 2020. One non-peer-reviewed study collected data from June 2020 to March 2021 (9) and one other study collected data from December 2020 to May 2021 (25). As in prior updates, new studies had methodological limitations including potential recall bias, limited control of confounders, and low or unclear participation rates.
New evidence was consistent with prior updates in finding no consistent association between risk of SARS-CoV-2 infection in HCWs and age (13 studies (6, 8, 10, 11, 14-17, 19, 22-25)), sex (13 studies (6, 8, 10, 11, 13, 14, 16, 17, 19, 22-25)), or HCW role (15 studies (6, 7, 11-16, 19-25)) (Appendix Table 2). Also consistent with prior update, 5 studies conducted in the United States, Canada, or Ireland found non-White race (Black, Asian or Asian/Pacific Islander, or combined non-White races) or Hispanic ethnicity associated with increased risk of infection (Appendix Table 2) (6, 8, 11, 15, 16).
Thirteen new studies reported on the association between exposures and likelihood of infection (Appendix Table 3) (6-8, 11, 12, 14, 16, 17, 19, 20, 23-25). Seven studies (7, 8, 12, 19, 20, 23, 24) consistently found exposure to COVID-19 in a household or private setting associated with increased risk of HCW SARS-CoV-2 infection; adjusted ORs ranged from 2.55 to 8.98 (Appendix Table 3). In most studies, household or private setting exposure was a stronger risk factor than work exposure. Nine studies found direct contact in a work environment to patients with COVID-19 associated with increased infection risk (7, 8, 11, 12, 17, 19, 23-25).
No new study evaluated the association between education or training (Appendix Table 4) and risk of HCW infection. One non-peer-reviewed study (9) based on data collected from June 2020 to March 2021 (mostly before the emergence of the delta variant) found primarily using filtering facepiece 2 (FFP2) masks associated with decreased risk of SARS-CoV-2 infection versus primarily using surgical masks (adjusted OR for seroconversion 0.73, 95% CI 0.53 to 1.00) (Appendix Table 5).
Two new studies (10, 18) examined other infection prevention and control measures and risk of SARS-CoV-2 infection (Appendix Table 6). One study found glove use (adjusted OR 2.93, 95% CI 1.19 to 7.22) associated with an increased risk of infection compared with non-use; estimates for gown use (adjusted OR 0.64, 95% CI 0.31 to 1.32) and goggle use (adjusted OR 1.27, 95% CI 0.72-2.27) were imprecise (10). The other study (18) found being a frontline HCW and performing an aerosol-generating procedure on a COVID-19 patient without appropriate PPE (including mask, apron, gown and/or gloves) associated with increased risk of infection versus not being a frontline worker (adjusted OR 2.39, 95% CI 1.00 to 6.18). Both studies were limited with regard to controlling for exposures and other confounders, including adherence to personal protective equipment use.
Evidence across all risk factors is summarized in Appendix Table 7. Despite large numbers of studies and participants, most evidence remains low or moderate certainty because of methodological limitations, imprecision, and inconsistency.
References
Disclosures:
Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M21-4294.
Update Alert 7: Epidemiology of and Risk Factors for Coronavirus Infection in Health Care Workers
This is the tenth update alert for a living review on the epidemiology of and risk factors for coronavirus infection in health care workers (HCWs) (1). Initial updates were monthly through Update Alert #7 (2), then bimonthly for Update Alerts #8 (3) and 9 (4), which focused on risk factors for coronavirus infection. Beginning with this update, we limited inclusion to studies that reported adjusted risk estimates, to focus on higher quality evidence, and the update interval was extended to biannually, given stable findings in prior updates. We excluded non-peer-reviewed studies, except for studies comparing mask types conducted in or after January 2021, when the delta variant emerged. Searches for this update were conducted from April 25, 2021 to October 24, 2021, using the same search strategies as the original review, and identified 8,656 citations. We applied the same inclusion criteria used for prior updates, other than described above. Twenty studies on risk factors for SARS-CoV-2 infection were added for this update (Appendix Tables 1-6) (6-25).
The original rapid review included 34 studies on risk factors for coronavirus infections (3 studies on SARS-CoV-2, 29 studies on SARS-CoV-1, and 2 studies on MERS-CoV) (1); 93 studies (91 studies on SARS-CoV-2, 0 studies on SARS-CoV-1, and 2 studies on MERS-CoV) were added in prior updates (2-5, 26-29). For this update, four cohort studies (6-9) (including one pre-print study (9)), 15 cross-sectional studies (10-24), and one case-control study (25), all on SARS-CoV-2, were added (Appendix Table 1). Ten studies were conducted in Europe and seven were conducted in North America. The others were conducted in Kuwait, Qatar, and Turkey. In 18 studies, data were collected from February to December 2020. One non-peer-reviewed study collected data from June 2020 to March 2021 (9) and one other study collected data from December 2020 to May 2021 (25). As in prior updates, new studies had methodological limitations including potential recall bias, limited control of confounders, and low or unclear participation rates.
New evidence was consistent with prior updates in finding no consistent association between risk of SARS-CoV-2 infection in HCWs and age (13 studies (6, 8, 10, 11, 14-17, 19, 22-25)), sex (13 studies (6, 8, 10, 11, 13, 14, 16, 17, 19, 22-25)), or HCW role (15 studies (6, 7, 11-16, 19-25)) (Appendix Table 2). Also consistent with prior update, 5 studies conducted in the United States, Canada, or Ireland found non-White race (Black, Asian or Asian/Pacific Islander, or combined non-White races) or Hispanic ethnicity associated with increased risk of infection (Appendix Table 2) (6, 8, 11, 15, 16).
Thirteen new studies reported on the association between exposures and likelihood of infection (Appendix Table 3) (6-8, 11, 12, 14, 16, 17, 19, 20, 23-25). Seven studies (7, 8, 12, 19, 20, 23, 24) consistently found exposure to COVID-19 in a household or private setting associated with increased risk of HCW SARS-CoV-2 infection; adjusted ORs ranged from 2.55 to 8.98 (Appendix Table 3). In most studies, household or private setting exposure was a stronger risk factor than work exposure. Nine studies found direct contact in a work environment to patients with COVID-19 associated with increased infection risk (7, 8, 11, 12, 17, 19, 23-25).
No new study evaluated the association between education or training (Appendix Table 4) and risk of HCW infection. One non-peer-reviewed study (9) based on data collected from June 2020 to March 2021 (mostly before the emergence of the delta variant) found primarily using filtering facepiece 2 (FFP2) masks associated with decreased risk of SARS-CoV-2 infection versus primarily using surgical masks (adjusted OR for seroconversion 0.73, 95% CI 0.53 to 1.00) (Appendix Table 5).
Two new studies (10, 18) examined other infection prevention and control measures and risk of SARS-CoV-2 infection (Appendix Table 6). One study found glove use (adjusted OR 2.93, 95% CI 1.19 to 7.22) associated with an increased risk of infection compared with non-use; estimates for gown use (adjusted OR 0.64, 95% CI 0.31 to 1.32) and goggle use (adjusted OR 1.27, 95% CI 0.72-2.27) were imprecise (10). The other study (18) found being a frontline HCW and performing an aerosol-generating procedure on a COVID-19 patient without appropriate PPE (including mask, apron, gown and/or gloves) associated with increased risk of infection versus not being a frontline worker (adjusted OR 2.39, 95% CI 1.00 to 6.18). Both studies were limited with regard to controlling for exposures and other confounders, including adherence to personal protective equipment use.
Evidence across all risk factors is summarized in Appendix Table 7. Despite large numbers of studies and participants, most evidence remains low or moderate certainty because of methodological limitations, imprecision, and inconsistency.
References
Disclosures:
Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=L21-0034.
Update Alert 11: Epidemiology of and Risk Factors for Coronavirus Infection in Health Care Workers
This is the eleventh and final update alert for a living rapid review on the epidemiology of and risk factors for coronavirus infection in health care workers (HCWs) (1). Updates were monthly through Update Alert #7 (2), bimonthly for Updates #8 (3) and 9 (4), then biannual. Searches for this update were conducted from October 25, 2021 to May 24, 2022, using the same search strategies as the original review. The update searches identified 8,552 citations. We applied the same inclusion criteria used for prior updates, with previously (5) described protocol modifications to focus on risk factors for coronavirus infections and higher quality evidence (studies reporting adjusted risk estimates).
The original rapid review included 34 studies on risk factors for coronavirus infections (3 studies on SARS-CoV-2) (1); 124 studies (122 studies on SARS-CoV-2) were added in prior updates (2-10). Twenty new studies on risk factors for SARS-CoV-2 infection were added for this update (Appendix Tables 1-8) (11-30). The studies were based on data collected through the end of 2020 in ten studies (11-13, 15-17, 23, 24, 27, 30) and through June 2021 in nine studies (14, 18-22, 25, 26, 29). One new study collected data in South Africa in November and December 2021, during the initial Omicron variant surge (28). Of the 20 new studies, 7 were cohort studies (14, 16, 20, 23, 25, 26, 29), 12 were cross-sectional studies (11-13, 15, 17-19, 22, 24, 27, 28, 30), and one was a case-control study (21) (Appendix Table 1). Ten studies were conducted in Europe, three in Africa, one in the Middle East, and five in North America. As with previously included studies, the new studies had methodological limitations including potential recall bias, limited adjustment for potential confounders (including SARS-CoV-2 exposures), and low or unclear participation rates.
The new studies were generally consistent with prior updates on the association between demographic characteristics and risk of SARS-CoV-2 infection in HCWs (Appendix Table 2). There was no consistent association between age (16 studies (11, 13, 14, 16-27, 29)) or sex (16 studies (11, 13, 14, 16-27, 29)) and risk of SARS-CoV-2 infection. Seven new studies were consistent with prior evidence suggesting increased risk of SARS-CoV-2 infection among Black or Hispanic HCWs compared with White or non-Hispanic HCWs (12, 13, 18, 20, 23, 26, 27). Sixteen new studies evaluated the association between various HCW roles and risk of infection, most commonly nurse versus physician (12-14, 17-27, 29, 30). Among eleven studies, eight studies found being a nurse associated with higher risk of SARS-CoV-2 infection than being a physician and three studies found similar risk. The new studies did not change the overall finding of no clear association between nurse versus physician HCW role and risk of SARS-CoV-2 infection, given inconsistency in findings, including prior studies showing physicians being at higher risk.
New for this update, three studies found prior COVID-19 infection or positive vaccination status associated with decreased risk of SARS-CoV-2 re-infection/infection among HCWs (Appendix Table 3) (26, 28, 29). In one study conducted during the Omicron variant surge, prior PCR-confirmed SARS-CoV-2 infection was associated with decreased risk of re-infection (adjusted odds ratio [OR] 0.55, 95% CI 0.36 to 0.84) (28). In this study, HCWs with two doses of the BNT162b2 vaccine were at decreased risk of infection compared to those unvaccinated, though the difference was not statistically significant (adjusted OR 0.59, 95% CI 0.23 to 1.57). One pre-Omicron study found prior infection associated a reduced risk of reinfection among unvaccinated persons (adjusted incidence rate ratio 0.15, 95% CI 0.08 to 0.26) and full vaccination (2 doses) associated with decreased risk versus no vaccination (adjusted incidence rate ratio 0.10, 95% CI 0.02 to 0.38) (26) and another pre-Omicron study found full vaccination associated with decreased risk versus no vaccination (adjusted HR 0.37, 95% CI 0.29 to 0.69) (29).
Fourteen new studies reported on the association between exposures and likelihood of HCW SARS-CoV-2 infection (Appendix Table 4) (11-13, 15-22, 24, 26, 30). As in prior updates, greater exposure was generally associated with increased risk of SARS-CoV-2 infection. Thirteen studies found direct contact with a COVID-19 patient or working in a setting at high-risk of exposure to a COVID-19 infected patient associated with increased risk of SARS-CoV-2 infection versus no direct contact or working in a lower-risk setting, but risk estimates were imprecise or not consistently statistically significant in most studies, and exposure definitions and comparisons varied (11-13, 15-22, 24, 26). No new study evaluated the association between education or training and risk of SARS-CoV-2 infection (Appendix Table 5).
Three new studies reported on the association between mask use and SARS-CoV-2 infection (Appendix Table 6). One new publication for a previously included study found use of an N95 mask associated with increased risk of SARS-CoV-2 infection versus non-use in a univariate analysis (OR 7.8, 95% CI 4.0 to 15.2) (16). However, N95 use was not included in the multivariate model and the observed association is likely related to confounding from increased exposures or other factors in HCWs using N95s. Two other new studies of mask use are consistent with prior updates that suggest mask use reduces risk of SARS-CoV-2 infection, but risk estimates were not statistically significant (20, 23). Neither study reported mask type and both were susceptible to potential recall bias.
Consistent with previously reviewed evidence, one new study found appropriate use of PPE associated with decreased risk of SARS-CoV-2 infection compared with suboptimal use when participating in a number of patient care activities (Appendix Table 7) (15). However, findings were limited by unclear definitions for “appropriate” and “suboptimal” PPE use.
A summary of all evidence identified through this final update is shown Appendix Table 8. Despite large numbers of studies and participants, evidence remains low for most risk factors due to limited evidence, methodological limitations, imprecision, and inconsistency. Moderate evidence indicates no association between age, sex, or HCW role (nurse vs. physician) and risk of SARS-CoV-2 infection, an association between Black race or Hispanic ethnicity (vs. White race or non-Hispanic ethnicity) and increased risk of SARS-CoV-2 infection, and an association between PPE use and decreased risk of SARS-CoV-2 infection.
References
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Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=L22-0235.