Effectiveness of COVID-19 vaccines against Omicron and Delta hospitalisation, a test negative case-control study.

ABSTRACT: The Omicron variant has been associated with reduced vaccine effectiveness (VE) against mild disease with rapid waning. Meanwhile Omicron has also been associated with milder disease. Protection against severe disease has been substantially higher than protection against infection with previous variants. We used a test-negative case-control design to estimate VE against hospitalisation with the Omicron and Delta variants using PCR testing linked to hospital records. We investigated the impact of increasing the specificity and severity of hospitalisation definitions on VE. Among 18-64-year-olds using cases admitted via emergency care, VE after a 3rd dose peaked at 82.4% and dropped to 53.6% by 15+ weeks after the 3rd dose; using all admissions for > = 2 days stay with a respiratory code in

SUBMITTER: Stowe J 

PROVIDER: S-EPMC9523190 | biostudies-literature | 2022 Sep

REPOSITORIES: biostudies-literature