Medical masks vs N95 respirators for preventing COVID‐19 in healthcare workers: A systematic review and meta‐analysis of randomized trials
Our systematic review update identified 1 new randomized trial (n = 5180) eligible for meta‐analysis following screening of 389 titles and abstracts, and 12 full‐texts (Figure 1).18 To date, there have been four trials where healthcare workers providing care for patients with acute febrile illness were randomized to medical masks (n = 3957) or N95 respirators (n = 4779), of which 3 were identified from a 2016 systematic review (Table 1)
see the paper
Forty‐one healthcare workers were exposed to aerosol‐generating procedures from a patient with severe pneumonia, who later tested positive for SARS‐CoV‐2 during COVID‐19 surveillance. These procedures included endotracheal intubation, extubation, non‐invasive ventilation, and exposure to aerosols in an open circuit. All of the exposed healthcare workers tested negative 14 days after their date of exposure, despite 85% (35/41) having worn surgical masks during the high‐risk procedures.26 Given the limited direct evidence from this case‐report, further research on the risk of secondary infection in healthcare workers caring for COVID‐19 patients is warranted.
There are several limitations in this meta‐analysis. First, only one trial individually studied cases of coronavirus infection between medical masks and N95 respirators; therefore, we were unable to meta‐analyze coronavirus infection specifically. This led us to downgrade the evidence with GRADE as it relates to indirectness because our findings may not be generalizable to SARS‐CoV‐2.
With the widespread of SARS‐CoV‐2, a serious concern is that stockpiles of N95 respirators will be depleted. The Department of Health and Human Services announced that its Strategic National Stockpile—the emergency stockpile of drugs and medical supplies in the United States—contained approximately 30 million medical masks and 12 million N95 respirators. This stockpile of respiratory protective devices equates to 1% of the estimated amount needed for U.S HCWs in a pandemic scenario (42 million stockpiled compared with the estimated 3.5 billion needed).28 Based on the evidence, preservation of N95 respirators for high‐risk, aerosol‐generating procedures in this pandemic should be considered when in short supply. The uncertainty of this evidence and the depleting stockpiles of respiratory protective devices emphasize the need for further comparative research of medical masks and N95 respirators.
https://onlinelibrary.wiley.com/doi/ful ... /irv.12745
What does it mean? They don't know. The n95 masks can't be worse, so use them if possible, for healthcare workers.