Physical interventions to interrupt or reduce the spread of respiratory viruses.

Abstract (PubMed)

BACKGROUND: Viral epidemics or pandemics of acute respiratory infections (ARIs) pose a global threat. Examples are influenza (H1N1) caused by the H1N1pdm09 virus in 2009, severe acute respiratory syndrome (SARS) in 2003, and coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 in 2019. Antiviral drugs and vaccines may be insufficient to prevent their spread. This is an update of a Cochrane Review last published in 2020. We include results from studies from the current COVID-19 pandemic. OBJECTIVES: To assess the effectiveness of physical interventions to interrupt or reduce the spread of acute respiratory infections. SEARCH METHODS: We searched CENTRAL, PubMed, Embase and CINAHL from the inception of each database to 1 April 2022. MAIN RESULTS: We included 78 randomised trials (RCTs) with 610,872 participants. Medical/surgical masks compared to no masks probably makes little or no difference to the outcome of influenza-like illness (ILI) compared to no masks (RR 1.01, 95% CI 0.72 to 1.42; 9 RCTs; n=3507). N95/P2 respirators compared to medical/surgical masks makes little or no difference to the outcome of ILI (RR 1.06, 95% CI 0.90 to 1.25; 11 RCTs; n=28,746). Hand hygiene compared to control probably makes little or no difference to the outcome of COVID-19 (RR 0.86, 95% CI 0.60 to 1.23; low certainty evidence). CONCLUSIONS: The high risk of bias in the trials, variation in outcome measurement, and relatively low adherence with the interventions during the studies hampers drawing firm conclusions.