Publications

In the UK, COVID-19 vaccination for adults began in December, 2020. Because children and adolescents have a low risk of severe COVID-19 and due to concerns about rare but potentially severe myocarditis after mRNA vaccination—mainly after the second dose in young adult males—the UK Joint Committee on Vaccination and Immunisation (JCVI) initially recommended one dose for 16–17-year-olds from Aug 4, 2021, and recommended against vaccinating 12–15-year-olds because of marginal benefits versus risk. UK ministers subsequently recommended vaccinating this group with BNT162b2 (Comirnaty, Pfizer-BioNTech) or mRNA-1273 (Spikevax, Moderna) from Sept 13, 2021, to prevent education disruption. Contrary to the authorised 3-week interval, the UK recommends 8–12 weeks between doses, because of the high protection provided by the first dose and higher antibody responses after a later second dose. The UK strategy provided a unique opportunity to assess single-dose mRNA vaccine effectiveness in adolescents during a period of high community infection with the highly transmissible delta (B.1.617.2) variant and subsequently with the more transmissible, and now dominant, omicron (B.1.1.529) variant.