Mass testing for discovery and control of COVID-19 outbreaks in adult social care: an observational study and cost-effectiveness analysis of 14,805 care homes in England
Authors: Chen Siyu , Creswell Richard , Hounsell Rachel , Cantrell Liberty , Bajaj Sumali , Dahal Prabin , Tsui Lok Hei , Kolade Olumide , Amswych Ma’ayan , Naidoo Reshania , Fowler Tom , Hopkins Susan , Stepniewska Kasia , Voysey Merryn , White Lisa , Shretta Rima , Lambert Ben 
Published: June 2024

AbstractIntroductionWe retrospectively evaluated the impact of COVID-19 testing among residents and staff in social care homes in England.MethodsWe obtained 80 million reported polymerase chain reaction (PCR) and lateral flow device (LFD) test results, from 14,805 care homes (residents and staff) in England, conducted between October 2020 and March 2022. These testing data were then linked to care home characteristics, test costs and 24,500 COVID-19-related deaths of residents. We decomposed the mechanism of outbreak mitigation into outbreak discovery and outbreak control and used Poisson regressions to investigate how reported testing intensity was associated with the size of outbreak discovered and to uncover its association with outbreak control. We used negative binomial regressions to determine the factors influencing COVID- 19-related deaths subsequent to outbreaks. We performed a cost-effectiveness analysis of the impact of testing for preventing COVID-19-related deaths of residents.ResultsReported testing intensity generally reflected changes in testing policy over time, although there was considerable heterogeneity among care homes. Client type was the strongest determinant of whether COVID-19-related deaths in residents occurred subsequent to testing positive. Higher staff-to-resident ratios were associated with larger outbreak sizes but rapid outbreak control and a decreased risk of COVID-19-related deaths. Assuming our regression estimates represent causal effects, care home testing in England was cost effective at preventing COVID-19-related deaths among residents during the pandemic and approximately 3·5-times more cost effective prior to the vaccine rollout.ConclusionsPCR and LFD testing was likely an impactful intervention for detecting and controlling COVID-19 outbreaks in care homes in England and cost effective for preventing COVID-19- related deaths among residents. In future pandemics, testing must be prioritised for care homes, especially if severe illness and death particularly affects older people or individuals with characteristics similar to care home residents, and an efficacious vaccine is unavailable.Key MessagesEvidence before this studyMass diagnostic testing plays a key role in any pandemic response. COVID-19 testing in the adult social care sector in England was implemented by NHS Test and Trace (later the UK Health Security Agency, UKHSA). Prior to the large-scale evaluation we report here, a pilot testing evaluation programme had been conducted in Liverpool.Added value of this studyThis study represents the first large-scale evaluation of England’s COVID-19 testing programme in adult social care homes. It encompasses data from residents and staff from 14,805 adult social care homes in England. Our findings show that testing was an important and useful public health intervention that had a considerable impact. It was also cost effective at preventing COVID-19-related deaths in adult social care home residents.Implications of all the available evidenceOur study has implications for the development of testing policies in adult social care homes in any future pandemic, particularly if it involves a respiratory disease similar to COVID-19. We found that while testing was a crucial public health intervention in adult social care homes, there were also large heterogeneities seen among care homes. Policymakers thus need to consider whether a one-size-fits-all policy for care home testing is the most effective approach to take in the face of any future pandemic.