Assessment of mortality and hospital admissions associated with confirmed infection with SARS-CoV-2 Alpha variant: a matched cohort and time-to-event analysis, England, October to December 2020

Gavin Dabrera*, Hester Allen, Asad Zaidi, Joe Flannagan, Katherine Twohig, Simon Thelwall, Elizabeth Marchant, Nurin Abdul Aziz, Theresa Lamagni, Richard Myers, André Charlett, Fernando Capelastegui, Dimple Chudasama, Tom Clare, Flavien Coukan, Mary Sinnathamby, Neil Ferguson, Susan Hopkins, Meera Chand, Russell HopeMeaghan Kall

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Background: The emergence of the SARS-CoV-2 Alpha variant in England coincided with a rapid increase in the number of PCR-confirmed COVID-19 cases in areas where the variant was concentrated. Aim: Our aim was to assess whether infection with Alpha was associated with more severe clinical outcomes than the wild type. Methods: Laboratory-confirmed infections with genomically sequenced SARS-CoV-2 Alpha and wild type between October and December 2020 were linked to routine healthcare and surveillance data-sets. We conducted two statistical analyses to compare the risk of hospital admission and death within 28 days of testing between Alpha and wild-type infections: a matched cohort study and an adjusted Cox proportional hazards model. We assessed differences in disease severity by comparing hospital admission and mortality, including length of hospitalisation and time to death. Results: Of 63,609 COVID-19 cases sequenced in England between October and December 2020, 6,038 had the Alpha variant. In the matched cohort analysis, we matched 2,821 cases with Alpha to 2,821 to cases with wild type. In the time-to-event analysis, we observed a 34% increased risk in hospitalisation associated with Alpha compared with wild type, but no significant difference in the risk of mortality. Conclusion: We found evidence of increased risk of hospitalisation after adjusting for key confounders, suggesting increased infection severity associated with the Alpha variant. Rapid assessments of the relative morbidity in terms of clinical outcomes and mortality associated with emerging SARS-CoV-2 variants compared with dominant variants are required to assess overall impact of SARS-CoV-2 mutations.

Original languageEnglish
JournalEurosurveillance
Volume27
Issue number20
DOIs
Publication statusPublished - 19 May 2022

Bibliographical note

Publisher Copyright:
© 2022 European Centre for Disease Prevention and Control (ECDC). All rights reserved.

Fingerprint

Dive into the research topics of 'Assessment of mortality and hospital admissions associated with confirmed infection with SARS-CoV-2 Alpha variant: a matched cohort and time-to-event analysis, England, October to December 2020'. Together they form a unique fingerprint.

Cite this