Notice of Retraction: Effectiveness of Surgical and Cotton Masks in Blocking SARS-CoV-2
FREEAccording to recommendations by the editors of Annals of Internal Medicine, we are retracting our article, “Effectiveness of Surgical and Cotton Masks in Blocking SARS-CoV-2. A Controlled Comparison in 4 Patients,” which was published at Annals.org on 6 April 2020 (1).
We had not fully recognized the concept of limit of detection (LOD) of the in-house reverse transcriptase polymerase chain reaction used in the study (2.63 log copies/mL), and we regret our failure to express the values below LOD as “<LOD (value).” The LOD is a statistical measure of the lowest quantity of the analyte that can be distinguished from the absence of that analyte. Therefore, values below the LOD are unreliable and our findings are uninterpretable. Reader comments raised this issue after publication. We proposed correcting the reported data with new experimental data from additional patients, but the editors requested retraction.
Reference
- 1.
Bae S ,Kim MC ,Kim JY ,et al . Effectiveness of surgical and cotton masks in blocking SARS-CoV-2: a controlled comparison in 4 patients. Ann Intern Med. Epub 6 April 2020. [PMID:32251511 ]. doi:10.7326/M20-1342 MedlineGoogle Scholar

The author's interpretation of their results was misleading
A big problem with this study was the peculiar interpretation of the results by the authors. Their results, given in log copies per mL, show that surgical masks reduced median viral emission by 27.5% and cotton masks reduced median viral emission by 80.4%. Just the fact that a reusable cotton mask was more effective than a manufactured surgical mask was news worthy by itself. Instead, the public was misled to believe the masks were totally ineffective.
It is hard to understand how the authors deemed that an 80% reduction of viral emission constitutes an “ineffective” intervention. With 80% reduction of viral emissions writ large, tens of thousands who have died of Covid-19 might be alive today. Cotton masks have never been promoted as 100% effective, not even N95 masks are. So setting that up as a rigid pass-fail metric was misleading and has endangered public health by obfuscating important degrees of efficacy.
Response from Editors
Bae and colleagues proposed to provide additional data from new experiments done on additional patients. Such information would not correct the problems with the published study and should be evaluated as a new study. The editors continue to believe that the appropriate action was to retract the article. We would welcome the opportunity to review a new study with appropriately presented, interpretable data.
Concerned that the editors wouldn't allow you to update your study