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Adolescent vaccination with BNT162b2 (Comirnaty, Pfizer-BioNTech) vaccine and effectiveness against COVID-19: national test-negative case-control study, England

2021; Cold Spring Harbor Laboratory; Linguagem: Inglês

10.1101/2021.12.10.21267408

Annabel Powell, Freja Kirsebom, Julia Stowe, Kelsey McOwat, Vanessa Saliba, Mary Ramsay, Jamie Lopez Bernal, Nick Andrews, Shamez Ladhani,

Animal Virus Infections Studies

Abstract Adolescents in the UK were recommended to have their first dose of mRNA vaccine during a period of high community transmission due to the highly transmissible Delta variant, followed by a second dose at an extended interval of 8-12 weeks. We used national SARS-CoV-2 testing, vaccination and hospitalisation data to estimate vaccine effectiveness (VE) using a test-negative case-control design, against PCR-confirmed symptomatic COVID-19 in England. BNT162b2 vaccination in 12-15-year-olds and 16-17-year-olds was associated with lower VE against symptomatic COVID-19 caused by Omicron compared to Delta. Data shows a rapid increase in VE against symptomatic COVID-19 after the second dose for both Delta and Omicron, although this declines to 23% against Omicron after 70+ days. Very high protection was achieved for Delta against hospitalisation after one dose. Our data highlight the importance of the second vaccine dose for protection against symptomatic COVID-19 and raise important questions about the objectives of an adolescent immunisation programme. If prevention of infection is the primary aim, then regular COVID-19 vaccine boosters will be required.