Journal Article

Impact of vaccination on new SARS-CoV-2 infections in the United Kingdom

Rourke, Emma, Stoesser, Nicole, Bell, John I., Pritchard, Emma, Eyre, David W., Walker, A. Sarah, Diamond, Ian, Newton, John N., Farrar, Jeremy, VanSteenHouse, Harper, Crook, Derrick, Jones, Joel, Studley, Ruth, Gethings, Owen, Peto, Tim E. A., Pouwels, Koen B., Vihta, Karina-Doris, Matthews, Philippa C., House, Thomas, Bell, Iain

2021

Overview

The effectiveness of COVID-19 vaccination in preventing new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in the general community is still unclear. Here, we used the Office for National Statistics COVID-19 Infection Survey—a large community-based survey of individuals living in randomly selected private households across the United Kingdom—to assess the effectiveness of the BNT162b2 (Pfizer–BioNTech) and ChAdOx1 nCoV-19 (Oxford–AstraZeneca; ChAdOx1) vaccines against any new SARS-CoV-2 PCR-positive tests, split according to self-reported symptoms, cycle threshold value (<30 versus ≥30; as a surrogate for viral load) and gene positivity pattern (compatible with B.1.1.7 or not). Using 1,945,071 real-time PCR results from nose and throat swabs taken from 383,812 participants between 1 December 2020 and 8 May 2021, we found that vaccination with the ChAdOx1 or BNT162b2 vaccines already reduced SARS-CoV-2 infections ≥21 d after the first dose (61% (95% confidence interval (CI) = 54–68%) versus 66% (95% CI = 60–71%), respectively), with greater reductions observed after a second dose (79% (95% CI = 65–88%) versus 80% (95% CI = 73–85%), respectively). The largest reductions were observed for symptomatic infections and/or infections with a higher viral burden. Overall, COVID-19 vaccination reduced the number of new SARS-CoV-2 infections, with the largest benefit received after two vaccinations and against symptomatic and high viral burden infections, and with no evidence of a difference between the BNT162b2 and ChAdOx1 vaccines. Results from the Office of National Statistics COVID-19 Infection Survey in the United Kingdom demonstrate that the ChAdOx1 nCoV-19 and BNT162b2 vaccines reduce the incidence of new SARS-CoV-2 infections by up to 65% with a single dose and up to 80% after two doses, with no significant differences in efficacy observed between the two vaccines.

• Publisher: Nature Publishing Group US,Nature Publishing Group
• Subject: 692/308/409 / 692/699/255/2514 / 692/700/478/174 / Biomedical and Life Sciences / Biomedicine / Cancer Research / Confidence intervals / Coronaviruses / COVID-19 / COVID-19 vaccines / Households / Immunization / Infections / Infectious Diseases / Influence / Metabolic Diseases / Molecular Medicine / Neurosciences / Polls & surveys / Respiratory diseases / Severe acute respiratory syndrome coronavirus 2 / Statistics / Vaccination / Vaccines / Viral diseases