The impact of community asymptomatic rapid antigen testing on COVID-19 hospital admissions: a synthetic control study
Authors: Zhang Xingna , Barr Ben , Green Mark , Hughes David , Ashton Matthew , Charalampopoulos Dimitrios , García-Fiñana Marta , Buchan Iain 
Published: May 2022

AbstractObjectiveTo analyse the impact on hospital admissions for COVID-19 of large-scale, voluntary, public open access rapid testing for SARS-CoV-2 antigen in Liverpool (UK) between 6th November 2020 and 2nd January 2021.DesignSynthetic control analysis comparing hospital admissions for small areas in the intervention population to a group of control areas weighted to be similar in terms of prior COVID-19 hospital admission rates and socio-demographic factors.InterventionCOVID-SMART (Systematic Meaningful Asymptomatic Repeated Testing), a national pilot of large-scale, voluntary rapid antigen testing for people without symptoms of COVID-19 living or working in the City of Liverpool, deployed with the assistance of the British Army from the 6th November 2020 in an unvaccinated population. This pilot informed the UK roll-out of SARS-CoV-2 antigen rapid testing, and similar policies internationally.Main outcome measureWeekly COVID-19 hospital admissions for neighbourhoods in England.ResultsThe intensive introduction of COVID-SMART community testing was associated with a 43% (95% confidence interval: 29% to 57%) reduction in COVID-19 hospital admissions in Liverpool compared to control areas for the initial period of intensive testing with military assistance in national lockdown from 6th November to 3rd December 2020. A 25% (11% to 35%) reduction was estimated across the overall intervention period (6th November 2020 to 2nd January 2021), involving fewer testing centres, before England’s national roll-out of community testing, after adjusting for regional differences in Tiers of COVID-19 restrictions from 3rd December 2020 to 2nd January 2021.ConclusionsThe world’s first voluntary, city-wide SARS-CoV-2 rapid antigen testing pilot in Liverpool substantially reduced COVID-19 hospital admissions. Large scale asymptomatic rapid testing for SARS-CoV-2 can help reduce transmission and prevent hospital admissions.Summary boxWhat is already known on this topic–Previous studies on managing the spread of SARS-CoV-2 have identified asymptomatic transmission as significant challenges for controlling the pandemic.–Along with non-pharmaceutical measures, many countries rolled out population-based asymptomatic testing programmes to further limit transmission.–Evidence is required on whether large scale voluntary testing of communities for COVID-19 reduces severe disease, by breaking chains of transmission.What this study adds–The findings of this study suggest that large scale rapid antigen testing of communities for SARS-CoV-2, within an agile local public health campaign, can reduce transmission and prevent hospital admissions.–The results indicate that policy makers should integrate such testing into comprehensive, local public health programmes targeting high risk groups, supporting those required to isolate and adapting promptly to prevailing biological, behavioural and environmental circumstances.