Longer intervals and extra doses of ChAdOx1 nCoV-19 vaccine

• Type of Material: Article
• Authors: Elizabeth T Rogawski McQuade, University of Virginia; Alexander Breskin, NoviSci, Durham
• Language: English
• Date: 2021-09-11
• Publisher: Elsevier Ltd
• Publication Version: Final Published Version
• Copyright Statement: © 2021 Elsevier Ltd. All rights reserved.
• Final Published Version (URL): http://dx.doi.org/10.1016/S0140-6736(21)01817-1
• Title of Journal or Parent Work: The Lancet
• Volume: 398
• Issue: 10304
• Start Page: 933
• End Page: 935
• Keywords: ChAdOx1 nCoV-19; COVID-19; Vaccines; Humans; COVID-19 Vaccines; SARS-CoV-2
• Research Categories: Health Sciences, Public Health; Health Sciences, Epidemiology

Abstract

As the COVID-19 pandemic evolves, public health authorities continue to make unprecedented decisions about the deployment of limited supplies of vaccines against COVID-19. One strategy to maximise the number of people immunised is to delay the second dose of vaccine, as was implemented in the UK and elsewhere, including for the Oxford–AstraZeneca ChAdOx1 nCoV-19 (AZD1222) vaccine.1 This decision was supported by the original phase 1–3 trials (COV001, COV002, COV003, and COV005) that showed increased binding antibody responses and vaccine efficacy with an extended prime-boost interval (≥12 weeks vs <6 weeks).2 Because the trial protocols were amended during the enrolment periods of these trials, subcohorts received the second dose at varying intervals. In The Lancet, Amy Flaxman and colleagues3 used these differences in COV001 and COV002 to investigate the persistence of immunogenicity after a single dose of ChAdOx1 nCoV-19 in 480 individuals, the immunity after an extended interval (44–45 weeks) between the first and second doses in 30 individuals, and the antibody immune response to a third dose as a booster given 28–38 weeks after the second dose in 75 individuals. All participants included were aged 18–55 years, the majority were White (>90%), and approximately half were female.