Effectiveness of BNT162b2 mRNA vaccine third doses and previous infection in protecting against SARS-CoV-2 infections during the Delta and Omicron variant waves; the UK SIREN cohort study September 2021 to February 2022

Third doses of COVID-19 vaccines were widely deployed following primary vaccine course waning and emergence of the Omicron-variant. We investigated protection from third-dose vaccines and previous infection against SARS-CoV-2 infection during Delta-variant and Omicron-variant (BA.1& BA.2) waves in our frequently PCR-tested cohort of healthcare-workers.Relative effectiveness of BNT162b2 third doses and infection-acquired immunity was assessed by comparing the time to PCR-confirmed infection in boosted participants with those with waned dose-2 protection ( ≥254 days after dose-2), by primary series vaccination type.

Source: Journal of Infection - November 3, 2023 Category: Infectious Diseases Authors: Victoria J Hall, Ferdinando Insalata, Sarah Foulkes, Peter Kirwan, Dominic Sparkes, Ana Atti, Michelle Cole, Elen de Lacy, Lesley Price, Diane Corrigan, Colin S Brown, Jasmin Islam, The SIREN Study Group Source Type: research