Socioeconomic and temporal heterogeneity in SARS-CoV-2 exposure and disease in England from May 2020 to February 2023
Authors: Morgenstern Christian , Rawson Thomas , Hinsley Wes , Perez Guzman Pablo N. , Bhatt Samir , Ferguson Neil M. 
Published: November 2024

AbstractBackgroundThe COVID-19 pandemic had resulted in over 20.5 million confirmed cases and 175,000 deaths in England by December 2023. The pandemic’s impact varied significantly across different population groups, influenced by deprivation, ethnicity, and policy measures.MethodsWe analysed individual-level data on SARS-CoV-2 testing, hospitalisations, deaths, and vaccination records in England from May 2020 to February 2022. We used Poisson regression models to estimate incidence rate ratios (IRRs) for first pillar 2 PCR positive cases, associated hospitalisations, and deaths, adjusting for sex, ethnicity, deprivation, geographic region, age, and epidemiological week. Model selection was based on cross-validation and performance metrics (AIC, R2).FindingsThe data analysed included 12,310,485 first SARS-CoV-2 pillar 2 PCR-confirmed infections, 79,315 hospitalisations, and 107,823 deaths associated with the first SARS-CoV-2 infection. Significant differences were observed across IMD quintiles, with the most deprived areas showing higher incidence rate ratios (IRRs) for death (1.64, 95% CI: 1.60-1.67) and hospitalisation (1.80, 95% CI: 1.75-1.85) compared to the least deprived areas as the reference group for the entire study period. Ethnic disparities were also notable, with higher IRRs for death and hospitalisation for all non-White ethnicities relative to White ethnicities as the reference group. We note that the magnitude of IRRs, for both deprivation and ethnicities, declined from the wild-type to the omicron periods for severe outcomes. For cases, we observed IRRs above one for non-White ethnicities during the wild-type and alpha periods only. Vaccine effectiveness (VE) was also assessed, with models indicating a significant reduction in risk post-vaccination across all outcomes of interest.InterpretationDeprivation and ethnicity significantly influenced COVID-19 outcomes in England. For severe outcomes, pre-existing health inequalities lead to large and persistent disparities. For infections, both protective and support measures need to be structured with ethnicity and deprivation in mind in the early parts of a pandemic.FundingUK Medical Research Council, Schmidt Foundation, National Institute of Health Research, Community Jameel.Research in ContextEvidence before this studyThe COVID-19 pandemic has significantly impacted global health, and previous research has highlighted the role of socioeconomic factors, such as deprivation and ethnicity, in influencing outcomes. McGowan et al. found in a scoping review that 91% of studies showed significantly higher COVID-19 mortality in areas of social disadvantage relative to more affluent areas. A systematic review by Pan et al.2showed the impact of ethnicity on clinical outcomes in COVID-19. However, the impact of deprivation and ethnicity over different time periods of the COVID-19 pandemic and its interplay with public health measures is poorly understood.Added value of this studyThis study leverages extensive data from multiple sources, including PCR-confirmed COVID-19 cases, hospitalisation records, death registries, and vaccination databases, to comprehensively analyse COVID-19 outcomes in relation to deprivation and ethnicity across England. Using Poisson regression, we provide estimates of incidence rate ratios (IRR) associated with different levels of deprivation and ethnic backgrounds. This study also incorporates data on periods defined by dominant variants and public health measures, allowing for a more detailed examination of how these factors interact with local socioeconomic contexts to influence health outcomes.Implications of all the available evidenceThe findings underscore the importance of considering disparities in COVID-19 outcomes by deprivation and ethnicity and highlight the need for targeted strategies to address these inequalities. Policymakers should prioritise resource allocation and tailored interventions in high-risk areas to mitigate the adverse impacts of the pandemic. Furthermore, the effectiveness of vaccination programs should be continuously evaluated in the context of these socioeconomic determinants to enhance their efficacy and reach. This research contributes to the growing body of evidence supporting the need for an equitable public health response that addresses the specific needs of diverse populations across different localities before the pandemic by reducing health inequalities and in the pandemic response.