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/fullEvidence published up to October 2022.Background Influenza (H1N1) caused by the H1N1pdm09 virus in 2009Severe acute respiratory syndrome (SARS) in 2003Coronavirus 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 = 610,872Bringing the total number of RCTs to 78Medical/surgical masks compared to no masksWearing masks in the community probably makes little or no difference to the outcome of influenza‐like illnesswearing a mask may make little to no difference in how many people caught a flu-like illness/COVID-like illnessRisk ratio (RR) 0.95, (0.84 to 1.09)9 trials, n = 276,917 participantsModerate-certainty evidence.Wearing masks in the community probably makes little or no difference to the outcome of laboratory-confirmed influenza/SARS-CoV-2RR 1.01, (CI 0.72 to 1.42)6 trials, n = 13,919Moderate-certainty evidenceHarms were rarely measured and poorly reported(very low-certainty evidence).N95/P2 respirators compared to medical/surgical masksWe pooled trials comparing N95/P2 respirators with medical/surgical masksWe are very uncertain on the effects of N95/P2 respirators compared with medical/surgical masks on the outcome of clinical respiratory illnessCompared 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 influenzaRR 0.70, (0.45 to 1.10)N = 7,779Very low-certainty evidenceInfluenza like illnessN95/P2 respirators compared with medical/surgical masks may be effective for ILIRR 0.82N= 8,407 Low-certainty evidenceThe use of a N95/P2 respirators compared to medical/surgical masksProbably makes little or no difference for laboratory-confirmed influenza infectionRR 1.10N = 8,407Moderate-certainty evidenceRestricting pooling to healthcare workers made no difference to the overall findings. Harms were poorly measured and reportedDiscomfort wearing medical/surgical masks or N95/P2 respirators was mentioned in several studiesVery low-certainty evidenceOne new RCTMedical/surgical masks were non-inferior to N95 respiratorsN = 1,009 healthcare workers in four countries,providing direct care to COVID-19 patients.