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

Abstract

ObjectivesTo 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).DesignObservational 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.SettingEngland between 4thOctober 2020 and 21stFebruary 2021.Participants23 million people under Tier 3 restrictions, compared to a synthetic control group derived from 29 million people under Tier 2 restrictions.InterventionsImplementation of Tier 3 covid-19 restrictions in designated areas on 7thDecember 2020, with additional constraints on indoor and outdoor meetings and the hospitality sector compared to less stringent Tier 2 restrictions.Main Outcome MeasuresWeekly covid-19 related hospital admissions for neighbourhoods in England over a 12-week period following the interventions.ResultsThe 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).ConclusionsRegionally 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.SUMMARY BOXESWhat is already known on this topic— Previous studies of localised non-pharmaceutical interventions (NPIs) found that they could be effective in reducing covid-19 transmissions.— covid-19 hospitalisation was a key indicator of healthcare resource dynamics, encompassing supply, demand, burden, and allocation, during the pandemic.— There is a need for a detailed examination of the impact of specific localised restrictions in the UK, such as Tier 3 measures, on hospital admissions to inform targeted public health strategies.What this study adds— This study found that additional localised restrictions on outdoor gatherings and in the hospitality sector were effective in mitigating hospital admissions during the pandemic.How this study might affect research, practice or policy— This study provides evidence for future public health policies and preparedness strategies supporting the use of differential regional restrictions during pandemics.