Pattni, Karan, Hungerford, Daniel, Adams, Sarah, Buchan, Iain 
ORCID: 0000-0003-3392-1650, Cheyne, Christopher, García-Fiñana, Marta, Hall, Ian ORCID: 0000-0002-3033-2335, Hughes, David ORCID: 0000-0002-1287-9994, Overton, Christopher ORCID: 0000-0002-8433-4010, Zhang, Xingna ORCID: 0000-0002-8849-2112 et al (show 1 more authors)
(2021)
Effectiveness of the BNT162b2 (Pfizer-BioNTech) and the ChAdOx1 nCoV-19 (Oxford-AstraZeneca) vaccines for reducing susceptibility to infection with the Delta variant (B.1.617.2) of SARS-CoV-2
[Preprint]
Abstract
<h4>Background</h4> From January to May 2021 the alpha variant (B.1.1.7) of SARS-CoV-2 was the most commonly detected variant in the UK, but since then the Delta variant (B.1.617.2), first detected in India, has become the predominant variant. The UK COVID-19 vaccination programme started on 8th December 2020. Most vaccine effectiveness studies to date have focused on the alpha variant. We therefore aimed to estimate the effectiveness of the BNT162b2 (Pfizer-BioNTech) and the ChAdOx1 nCoV-19 (Oxford-AstraZeneca) vaccines in preventing infection with respect to the Delta variant in a UK setting. <h4>Methods</h4> We used anonymised public health record data linked to infection data (PCR) using the Combined Intelligence for Population Health Action resource. We then constructed an SIR epidemic model to explain SARS-CoV-2 infection data across the Cheshire and Merseyside region of the UK. <h4>Results</h4> We determined that the effectiveness of the Oxford-AstraZeneca vaccine in reducing susceptibility to infection is 39% (95% credible interval [34,43]) and 64% (95% credible interval [61,67]) for a single dose and a double dose respectively. For the Pfizer-BioNTech vaccine, the effectiveness is 20% (95% credible interval [10,28]) and 84% (95% credible interval [82,86]) for a single-dose and a double dose respectively. <h4>Conclusion</h4> Vaccine effectiveness for reducing susceptibility to SARS-CoV-2 infection shows noticeable improvement after receiving two doses of either vaccine. Findings also suggest that a full course of the Pfizer-BioNTech provides the optimal protection against infection with the Delta variant. This would advocate for completing the full course programme to maximise individual protection and reduce transmission.
| Item Type: | Preprint |
|---|---|
| Uncontrolled Keywords: | 3207 Medical Microbiology, 32 Biomedical and Clinical Sciences, Coronaviruses Vaccines, Prevention, Infectious Diseases, Coronaviruses, Vaccine Related, Immunization, Emerging Infectious Diseases, 3.4 Vaccines, Infection, 3 Good Health and Well Being |
| Divisions: | Faculty of Health & Life Sciences Faculty of Health & Life Sciences > Inst. Infection, Vet & Ecological Sciences Faculty of Health & Life Sciences > Inst. Population Health Faculty of Science & Engineering > School of Physical Sciences |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 19 Oct 2021 15:51 |
| Last Modified: | 29 Jan 2026 21:08 |
| DOI: | 10.1101/2021.10.12.21264840 |
| Open Access URL: | https://www.medrxiv.org/content/10.1101/2021.10.12... |
| Related Websites: | |
| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3140915 |
| Disclaimer: | The University of Liverpool is not responsible for content contained on other websites from links within repository metadata. Please contact us if you notice anything that appears incorrect or inappropriate. |
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