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ABSTRACT: Background
Two- and 3-dose BNT162b2 vaccine effectiveness (VE) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, including Delta and Omicron variants, was assessed among adolescents in Canada, where first and second doses were spaced longer than the manufacturer-specified 3-week interval.Methods
Test-negative design estimated VE against laboratory-confirmed SARS-CoV-2 infection ≥14 days after vaccination among 12-17-year-olds in Quebec and British Columbia, Canada, between 5 September 2021 and 30 April 2022 (epidemiological weeks 36-17). VE was explored by the interval between first and second doses, time since the second dose, and with a third dose.Results
The VE against Delta was ≥90% until at least 5 months after the second dose. The VE against Omicron decreased from about 65%-75% at 2-3 weeks to ≤50% by the third month after vaccination, restored to approximately 65% by a third dose. Although confidence intervals overlapped, VE against Omicron was about 5%-7% higher (absolute) when first and second doses were spaced ≥8 versus 3-4 weeks apart.Conclusions
In adolescents, 2 BNT162b2 doses provided strong and sustained protection against Delta but reduced and rapidly waning VE against Omicron. A longer interval between first and second doses and a third dose marginally improved Omicron protection.
SUBMITTER: Ionescu IG
PROVIDER: S-EPMC10132765 | biostudies-literature | 2023 Apr
REPOSITORIES: biostudies-literature
Ionescu Iulia G IG Skowronski Danuta M DM Sauvageau Chantal C Chuang Erica E Ouakki Manale M Kim Shinhye S De Serres Gaston G
The Journal of infectious diseases 20230401 9
<h4>Background</h4>Two- and 3-dose BNT162b2 vaccine effectiveness (VE) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, including Delta and Omicron variants, was assessed among adolescents in Canada, where first and second doses were spaced longer than the manufacturer-specified 3-week interval.<h4>Methods</h4>Test-negative design estimated VE against laboratory-confirmed SARS-CoV-2 infection ≥14 days after vaccination among 12-17-year-olds in Quebec and British Co ...[more]