key: cord-0273372-15u7l5x9
authors: Powell, A. A.; Kirsebom, F.; Stowe, J.; McOwat, K.; Saliba, V.; Ramsay, M. E.; Lopez Bernal, J.; Andrews, N.; Ladhani, S. N.
title: Adolescent vaccination with BNT162b2 (Comirnaty, Pfizer-BioNTech) vaccine and effectiveness of the first dose against COVID-19: national test-negative case-control study, England
date: 2021-12-11
journal: nan
DOI: 10.1101/2021.12.10.21267408
sha: cde193a796b1859e55ac80ae7f8bbb33dc834478
doc_id: 273372
cord_uid: 15u7l5x9

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. VE against symptomatic disease increased to 80% within two weeks of the first dose of BNT162b2 vaccine (higher than in adults aged 18-64 years) and then declines rapidly to 40% within 8 weeks (similar to adults). Early data in 16-17-year-olds also indicate high protection against hospitalisation and a rapid increase in VE against symptomatic COVID-19 after the second 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.

Children and adolescents have a low risk of severe COVID-19. 1 In the UK, COVID-19 vaccination for adults began in December 2020. 2 Because of 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 4 August 2021, 3 and recommended against vaccinating 12-15-year-olds because of marginal riskbenefits, 4 although UK ministers subsequently recommended vaccinating this group with BNT162b2 (Comirnaty, Pfizer-BioNTech) or mRNA-1273 (Spikevax, Moderna) from 13 September 2021 to prevent education disruption. 5 Contrary to the authorised 3-week interval, the UK recommends [8] [9] [10] [11] [12] weeks between doses, because of the high protection the first dose provides and higher antibody responses after a later second dose. 6 The UK strategy provided a unique opportunity to assess single-dose mRNA vaccine effectiveness (VE) in adolescents during a period of high community infection with the highly-transmissible Delta variant.

We used a test-negative case-control design to estimate VE after one BNT162b2 dose against PCRconfirmed symptomatic COVID-19 in England, as described previously. 7 is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted December 11, 2021. ; https://doi.org/10.1101/2021.12.10.21267408 doi: medRxiv preprint increased rapidly and plateaued at 95% at 2-9 weeks, also higher than adult VE in this period. This is, so far, the only VE evaluation after a single mRNA dose in adolescents. Pre-licensure trials reported 93% (mRNA-1273) to 100% (BNT162b2) efficacy in preventing COVID-19 among 12-15 year-olds from 7 days (BNT162b2) or 14 days (mRNA-1273) after two doses given 3-4 weeks apart, 9, 10 but the short interval between doses prevents comparison with our cohort. Real-world VE data against two BNT162b2 doses includes a US study using a similar test-negative case-control design estimating 93% (95%CI, 83%-97%) VE against hospitalisation during June-September 2021, 11 and another reporting 81% VE (95%CI, -55 to 90%) VE against hospitalisation in 12-15-year-olds, although this included only 45 cases, 12 whilst early Israeli data estimated 91.5% (95%CI, 88.2%-93.9%) VE against SARS-CoV-2 infection in 12-15-year-olds. 13 VE against symptomatic COVID-19 wanes quickly after the first dose and is also expected to wane after the second dose. The adolescent immunisation programme as a stand-alone intervention is unlikely to sustain suppression of infections in the medium-to-long term. If the aim of the programme is to reduce infections, then regular boosters will likely be needed. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted December 11, 2021. ; 

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