Randomized trials on non-pharmaceutical interventions for COVID-19 as of August 2021: a meta-epidemiological analysis

Abstract

Background: Numerous non-pharmaceutical interventions (NPIs) were taken worldwide to contain the spread of the COVID-19 pandemic. We aimed at providing an overview of randomized trials assessing NPIs to prevent COVID-19. Methods: We included all randomized trials assessing NPIs to prevent COVID-19 in any country and setting registered in ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform using the COVID-evidence platform (until 17 August 2021). We searched for corresponding publications in MEDLINE/PubMed, Google Scholar, the Living Overview of Evidence platform (L-OVE), and the Cochrane COVID-19 registry as well as for results posted in registries. Results: We identified 41 randomized trials. Of them, 11 were completed (26.8%) including 7 with published results. The 41 trials planned to recruit a median of 1,700 participants (IQR, 588 to 9,500, range 30 to 35,256,399) with a median planned duration of 8 months (IQR, 3 to 14, range 1 to 24). Most came from the United States (n=11, 26.8%). The trials mostly assessed protective equipment (n=11, 26.8%), COVID-19-related information and education programs (n=9, 22.0%), access to mass events under specific safety measures (n=5, 12.2%), testing and screening strategies (n=5, 12.2%), and hygiene management (n=5, 12.2%). Conclusions: Worldwide, 41 randomized trials assessing NPIs have been initiated with published results available to inform policy decisions for only 7 of them. A long-term research agenda including behavioral, environmental, social, and systems level interventions is urgently needed to guide policies and practices in the current and future public health emergencies.