Non-pharmaceutical interventions to prevent community transmission of infectious diseases with pandemic potential—an umbrella review and evidence map

During the COVID-19 pandemic, most countries implemented non-pharmaceutical interventions (NPIs) to mitigate virus transmission and decrease morbidity and mortality. The aim of this umbrella review was to identify and map systematic reviews on the effectiveness of NPIs to reduce widespread community transmission of infectious diseases with pandemic potential. We searched electronic databases (Medline, Embase, Scopus, INAHTA [International Network of Agencies for Health Technology Asseesment], and World Health Organization COVID-19) and websites (January 2024). Systematic reviews on NPIs during outbreaks, epidemics, or pandemics of COVID-19, severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), influenza, or Ebola were included and organized in an interactive evidence map grouped by type of intervention (individual/population/environmental), disease, risk of bias, and search date. Five of the 132 included reviews were assessed as having low, 43 moderate, and 84 high risk of bias. COVID-19 was targeted in 100 reviews, influenza 66, SARS 39, MERS 34, and Ebola in five reviews. The most frequently investigated NPIs were use of face masks, hand washing, physical distancing, travel restrictions, restrictions on public gatherings, and school closures. The five reviews at low risk of bias concluded at low level of evidence about the effectiveness of most NPIs, with exceptions of hand hygiene and some measures in school settings where low- to moderate-certainty evidence was found. There is substantial lack of evidence regarding the effectiveness of several commonly used NPIs, including restrictions on public gatherings, travel restrictions, and visiting restrictions in long-term care facilities. There is a paucity not only of systematic reviews but also of primary studies at low risk of bias.