Effectiveness of public health measures to prevent the transmission of SARS-CoV-2 at mass gatherings: A rapid review.

Mass gatherings play an important role in society, but since the onset of the Covid-19 pandemic, they have generally been restricted in order to mitigate transmission of SARS-CoV-2. The aim of this study was to summarise the evidence regarding the effectiveness of public health measures at preventing the transmission of SARS-CoV-2 at mass gatherings, and hence inform guidance on the organisation of these events. A rapid review was undertaken in Cochrane, Embase (OVID), Medline (OVID), Google, Web of Science and Europe PMC from 1 January 2020 to 3 June 2021. Of the identified 1,624 citations, 14 articles referring to 11 unique studies were included. This rapid review found evidence from 11 studies (involving approximately 30,482 participants) that implementing a range of measures may reduce the risk of SARS-CoV-2 transmission at mass gatherings; however, it is unlikely that this risk can be eliminated entirely. All studies adopted a layered mitigation approach involving multiple measures, which may be more effective than relying on any single measure. The number and intensity of measures implemented varied across studies, with most implementing resource intense measures. Importantly, all included studies were only of 'fair' to 'poor' quality. In conclusion, there is currently limited evidence on the effectiveness of measures to prevent SARS-CoV-2 transmission at mass gatherings. As mass gatherings recommence, continued adoption of known mitigation measures is required to limit the risk of transmission, as well as ongoing research and surveillance to monitor the potential impact of these events on the wider population and healthcare system.