Acute COVID-19 mortality in England in the Omicron era: a national level matched cohort study

Fluctuations in disease severity were observed throughout the COVID-19 pandemic in England associated with new variants and changes in population immunity.Deaths caused by COVID-19 reduced from 2022, however a smaller reduction was observed in deaths following a COVID-19 test.This study examines whether the risk of death within 28-days of a positive SARS-CoV-2 test remained elevated during a period associated with reduced disease severity.National level routinely collected health data was linked to create a cohort of individuals tested for SARS-CoV-2 throughout the pandemic with their vaccination, hospital and death records.Individuals testing positive and negative were matched on demographic and disease characteristics.The risk of death in both groups was calculated and univariable and multivariable conditional logistic regression models were used to compare the risk of death, for the overall study time-period (March 2020-April 2022) and the focus time-period (January-April 2022).During the overall time-period, individuals testing positive had a 228% increased risk of death compared to those testing negative, with risk peaking in early 2021.In the focused time-period the odds of death within 28 days of a SARS-Cov-2 test were 63% higher among test-positive individuals, after accounting for vaccination and previous hospitalisation.The risk was 238% higher among unvaccinated individuals who tested positive, compared to 155% among vaccinated individuals.Despite widespread vaccination coverage and reduced disease severity at the end of the pandemic, the risk of death following COVID-19 remained elevated, especially among unvaccinated individuals, supporting continued COVID-19 booster vaccination campaigns.