Effectiveness of non-pharmaceutical measures (NPIs) on COVID-19 in Europe: A systematic literature review

Background: The study objective was to conduct a systematic review to assess the effectiveness of non-pharmaceutical interventions (NPIs) to reduce the transmission of SARS-CoV-2 in Europe during the first wave of the pandemic. Methods: We searched OVID Medline, EMBASE, and the Cochrane and Campbell Databases for Systematic Reviews published up to April 15th 2021. Focusing on community (meso-level) and society (macro-level) level NPIs, we included all study designs, while a geographic restriction was limited to the EU, UK and European Economic Area (EEA) countries. Using the PICO framework, two reviewers independently extracted data and assessed quality using appropriate quality appraisal tools. A qualitative synthesis was performed, with NPIs grouped initially by a) Physical Distancing measures, b) Case detection and management measures, and c) hygiene measures and subsequently by country. Results: Of 17,692 studies initially assessed, 45 met all inclusion criteria. Most studies (n=30) had a modelling study design, while 13 were observational, one quasi-experimental and one experimental. Evidence from across the European continent, presented by country, indicates that the implementations of physical distancing measures (i.e., lockdowns/quarantines), preferably earlier in the pandemic, reduce the number of cases and hospitalisation across settings and for which the timing and duration are essential parameters. Case detection and management measures were also identified as effective measures at certain levels of testing and incidence, while hygiene and safety measures complemented the implementation of physical distancing measures. Conclusions: This literature review represents a comprehensive assessment of the effectiveness of NPIs in Europe up to April 2021. Despite heterogeneity across studies, NPIs, as assessed within the context of this systematic review at the macro and meso level, are effective in reducing SARS-CoV-2 transmission rates and COVID-19 hospitalisation rates and deaths in the European Region and may be applied as response strategies to reduce the burden of COVID-19 in forthcoming waves.