Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 2021 Nov;21(11):1539-1548.
doi: 10.1016/S1473-3099(21)00330-3. Epub 2021 Jun 23.

Effectiveness of BNT162b2 and ChAdOx1 nCoV-19 COVID-19 vaccination at preventing hospitalisations in people aged at least 80 years: a test-negative, case-control study

Catherine Hyams  1 , Robin Marlow  2 , Zandile Maseko  3 , Jade King  4 , Lana Ward  5 , Kazminder Fox  4 , Robyn Heath  4 , Anabella Tuner  4 , Zsolt Friedrich  5 , Leigh Morrison  5 , Gabriella Ruffino  5 , Rupert Antico  2 , David Adegbite  2 , Zsuzsa Szasz-Benczur  2 , Maria Garcia Gonzalez  2 , Jennifer Oliver  2 , Leon Danon  6 , Adam Finn  7
Affiliations
Comparative Study

Effectiveness of BNT162b2 and ChAdOx1 nCoV-19 COVID-19 vaccination at preventing hospitalisations in people aged at least 80 years: a test-negative, case-control study

Catherine Hyams et al. Lancet Infect Dis. 2021 Nov.

Erratum in

Abstract

Background: On Dec 8, 2020, deployment of the first SARS-CoV-2 vaccination authorised for UK use (BNT162b2 mRNA vaccine) began, followed by an adenoviral vector vaccine ChAdOx1 nCoV-19 on Jan 4, 2021. Care home residents and staff, frontline health-care workers, and adults aged 80 years and older were vaccinated first. However, few data exist regarding the effectiveness of these vaccines in older people with many comorbidities. In this post-implementation evaluation of two COVID-19 vaccines, we aimed to determine the effectiveness of one dose in reducing COVID-19-related admissions to hospital in people of advanced age.

Methods: This prospective test-negative case-control study included adults aged at least 80 years who were admitted to hospital in two NHS trusts in Bristol, UK with signs and symptoms of respiratory disease. Patients who developed symptoms before receiving their vaccine or those who received their vaccine after admission to hospital were excluded, as were those with symptoms that started more than 10 days before hospital admission. We did logistic regression analysis, controlling for time (week), sex, index of multiple deprivations, and care residency status, and sensitivity analyses matched for time and sex using a conditional logistic model adjusting for index of multiple deprivations and care residency status. This study is registered with ISRCTN, number 39557.

Findings: Between Dec 18, 2020, and Feb 26, 2021, 466 adults were eligible (144 test-positive and 322 test-negative). 18 (13%) of 135 people with SARS-CoV-2 infection and 90 (34%) of 269 controls received one dose of BNT162b2. The adjusted vaccine effectiveness was 71·4% (95% CI 46·5-90·6). Nine (25%) of 36 people with COVID-19 infection and 53 (59%) of 90 controls received one dose of ChAdOx1 nCoV-19. The adjusted vaccine effectiveness was 80·4% (95% CI 36·4-94·5). When BNT162b2 effectiveness analysis was restricted to the period covered by ChAdOx1 nCoV-19, the estimate was 79·3% (95% CI 47·0-92·5).

Interpretation: One dose of either BNT162b2 or ChAdOx1 nCoV-19 resulted in substantial risk reductions of COVID-19-related hospitalisation in people aged at least 80 years.

Funding: Pfizer.

PubMed Disclaimer

Conflict of interest statement

Declaration of interests CH is principal investigator of the Avon CAP study which is an investigator-led University of Bristol study funded by Pfizer and has previously received support from the NIHR in an academic clinical fellowship. JO is a co-investigator on the Avon CAP study. LD is further supported by UKRI through the JUNIPER consortium (grant number MR/V038613/1), MRC (grant number MC/PC/19067), EPSRC (EP/V051555/1 and The Alan Turing Institute, grant EP/N510129/1). AF is a member of the JCVI and is chair of WHO's European Technical Advisory Group of Experts on Immunization committee. In addition to receiving funding from Pfizer as chief investigator of this study, he leads another project investigating transmission of respiratory bacteria in families jointly funded by Pfizer and the Gates Foundation and is an investigator in trials of COVID-19 vaccines including ChAdOx1 nCOV-19, Janssen, and Valneva vaccines. The other authors have no relevant conflicts of interest to declare.

Figures

Figure 1
Figure 1
Study profile Total study cohort of 144 SARS-CoV-2-positive individuals divides into 135 BNT1626b vaccinated and unvaccinated cases and nine ChAdOx1 nCoV-19 vaccinated cases, with the 27 unvaccinated cases in the ChAdOx1 nCoV-19 group shared from the unvaccinated cases in the BNT1626b group. *Aged at least 80 years by March 31, 2021.
Figure 2
Figure 2
Euler diagram of study cohorts Total study cohort of 144 SARS-CoV-2-positive cases and 322 SARS-CoV-2-negative controls, separated into the BNT1626b group (135 test-positive and 269 test-negative) and ChAdOx1 nCoV-19 group (36 test-positive and 90 test-negative). The ChAdOx1 nCoV-19 group is smaller due to the later introduction of this vaccine (on Jan 4, 2021), thus only the subset of controls identified after this date were eligible for this analysis.
See this image and copyright information in PMC

Comment in

References

    1. WHO WHO coronavirus disease (COVID-19) dashboard. Feb 24, 2021. https://covid19.who.int/
    1. Polack FP, Thomas SJ, Kitchin N, et al. Safety and efficacy of the BNT162b2 mRNA Covid-19 Vaccine. N Engl J Med. 2020;383:2603–2615. - PMC - PubMed
    1. Dagan N, Barda N, Kepten E, et al. BNT162b2 mRNA Covid-19 vaccine in a nationwide mass vaccination setting. N Engl J Med. 2021;384:1412–1423. - PMC - PubMed
    1. Voysey M, Clemens SAC, Madhi SA, et al. Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK. Lancet. 2021;397:99–111. - PMC - PubMed
    1. Voysey M, Costa Clemens SA, Madhi SA, et al. Single-dose administration and the influence of the timing of the booster dose on immunogenicity and efficacy of ChAdOx1 nCoV-19 (AZD1222) vaccine: a pooled analysis of four randomised trials. Lancet. 2021;397:881–891. - PMC - PubMed

Publication types

MeSH terms