Masks, the jury returns

RCTs did not show a clear reduction in respiratory viral infection with the use of medical/surgical masks. There were no clear differences between the use of medical/surgical masks compared with N95/P2 respirators in healthcare workers, when used in routine care to reduce respiratory viral infection. Do physical measures such as hand-washing or wearing masks stop or slow down the spread of respiratory viruses? https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD006207.pub6/full Evidence published up to October 2022. Background Influenza (H1N1) caused by the H1N1pdm09 virus in 2009 Severe acute respiratory syndrome (SARS) in 2003 Coronavirus disease 2019 (COVID-19) Update of a Cochrane Review last published in 2020. We include results from studies from the current COVID-19 pandemic. Main results 11 new RCTs and cluster-RCTs n = 610,872 Bringing the total number of RCTs to 78 Medical/surgical masks compared to no masks Wearing masks in the community probably makes little or no difference to the outcome of influenza‐like illness wearing a mask may make little to no difference in how many people caught a flu-like illness/COVID-like illness Risk ratio (RR) 0.95, (0.84 to 1.09) 9 trials, n = 276,917 participants Moderate-certainty evidence. Wearing masks in the community probably makes little or no difference to the outcome of laboratory-confirmed influenza/SARS-CoV-2 RR 1.01, (CI 0.72 to 1.42) 6 trials, n = 13,919 Moderate-certainty evidence Harms were rarely measured and poorly reported (very low-certainty evidence). N95/P2 respirators compared to medical/surgical masks We pooled trials comparing N95/P2 respirators with medical/surgical masks We are very uncertain on the effects of N95/P2 respirators compared with medical/surgical masks on the outcome of clinical respiratory illness Compared with wearing medical or surgical masks, wearing N95/P2 respirators probably makes little to no difference in how many people have confirmed flu and may make little to no difference in how many people catch a flu-like illness, or respiratory illness. Confirmed influenza RR 0.70, (0.45 to 1.10) N = 7,779 Very low-certainty evidence Influenza like illness N95/P2 respirators compared with medical/surgical masks may be effective for ILI RR 0.82 N= 8,407 Low-certainty evidence The use of a N95/P2 respirators compared to medical/surgical masks Probably makes little or no difference for laboratory-confirmed influenza infection RR 1.10 N = 8,407 Moderate-certainty evidence Restricting pooling to healthcare workers made no difference to the overall findings. Harms were poorly measured and reported Discomfort wearing medical/surgical masks or N95/P2 respirators was mentioned in several studies Very low-certainty evidence One new RCT Medical/surgical masks were non-inferior to N95 respirators N = 1,009 healthcare workers in four countries, providing direct care to COVID-19 patients.