Evaluating the impacts of tiered restrictions introduced in England in December 2020 on covid-19 hospitalisations: a synthetic control study

Objectives To assess the impact of Tier 3 covid-19 restrictions implemented in December 2020 in England on covid-19 hospital admissions compared to Tier 2 restrictions, and its potential variations by neighbourhood deprivation levels and the prevalence of the Alpha variant (B.1.1.7). Design Observational study utilising a synthetic control approach. Comparison of changes in weekly hospitalisation rates in Tier 3 areas to a synthetic control group derived from Tier 2 areas. Setting England between 4th October 2020 and 21st February 2021. Participants 23 million people under Tier 3 restrictions, compared to a synthetic control group derived from 29 million people under Tier 2 restrictions. Interventions Implementation of Tier 3 covid-19 restrictions in designated areas on 7th December 2020, with additional constraints on indoor and outdoor meetings and the hospitality sector compared to less stringent Tier 2 restrictions. Main Outcome Measures Weekly covid-19 related hospital admissions for neighbourhoods in England over a 12-week period following the interventions. Results The introduction of Tier 3 restrictions was associated with a 17% average reduction in hospital admissions compared to Tier 2 areas (95% CI 13% to 21%; 8158 (6286 to 9981) in total)). The effects were similar across different levels of neighbourhood deprivation and prevalence of the Alpha variant (B.1.1.7). Conclusions Regionally targeted Tier 3 restrictions in England had a moderate but significant effect on reducing hospitalisations. The impact did not exacerbate socioeconomic inequalities during the pandemic. Our findings suggest that regionally targeted restrictions can be effective in managing infectious diseases. What is already known on this topic What this study adds How this study might affect research, practice or policy ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This research was funded by the National Institute for Health and Care Research Health Protection Research Unit (NIHR HPRU) in Gastrointestinal Infections, a partnership between UK Health Security Agency (UKHSA), the University of Liverpool and the University of Warwick (Award ID, NIHR200910), the NIHR Policy Research Programme (RESTORE; Award ID, NIHR202484), the NIHR Applied Research Collaboration Northwest Coast (NWC ARC) and The Pandemic Institute (formed of seven founding partners: The University of Liverpool, Liverpool School of Tropical Medicine, Liverpool John Moores University, Liverpool City Council, Liverpool City Region Combined Authority, Liverpool University Hospital Foundation Trust, and Knowledge Quarter Liverpool). The views expressed are those of the authors and not necessarily those of the NHS, the NIHR, the Department of Health and Social Care, Public Health England, or The Pandemic Institute. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: University Research Ethics Committee review is not required by the University of Liverpool for the secondary analysis of data that have been anonymised by an external party and are provided to the research team in a fully anonymised format. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes The small-area covid-19 hospital admissions data were made available by NHS Digital under data sharing agreement DARS-NIC-16656-D9B5T-v3.10 and are available through application to NHS Digital. All other data are publicly accessible, and code is available via the Liverpool City Region Civic Data Cooperative GitHub public repository https://github.com/civicdatacoop/tier3\_covid\_hospitalisation. [https://github.com/civicdatacoop/tier3\_covid\_hospitalisation][1] The small-area covid-19 hospital admissions data were made available by NHS Digital under data sharing agreement DARS-NIC-16656-D9B5T-v3.10 and are available through application to NHS Digital. All other data are publicly accessible, and code is available via the Liverpool City Region Civic Data Cooperative GitHub public repository [https://github.com/civicdatacoop/tier3\_covid\_hospitalisation][1]. [1]: https://github.com/civicdatacoop/tier3_covid_hospitalisation