ONS Infections Survey reveals vaccine effects

Data from UK COVID-19 Infection Survey are the first to show the impact of vaccination on antibody responses and new infections in the general population aged 16 years and older.

Last updated:
23 April 2021

The UK-wide study, with more than 400,000 people currently enrolled, led by the Office for National Statistics (ONS) and the Department of Health and Social Care (DHSC), draws on the world-leading scientific expertise of the University of Oxford to track the spread of the coronavirus (COVID-19) in the general population.  

The studies, released by Oxford University on 23 April 2021 as pre-prints, use ONS data to analyse the protection from infection provided by COVID-19 vaccines found that:

  • COVID-19 infections fell significantly -- by 65% percent -- after a first dose of the Oxford-AstraZeneca or Pfizer-BioNTech vaccines

  • two doses of the Pfizer-BioNTech vaccine offered similar levels of protection against COVID-19 as previous COVID-19 infection;too few people have yet received two doses of Oxford-AstraZeneca to assess this

  • vaccination was just as effective in individuals over 75 years or with underlying health conditions, as it was in those under 75 years or without health conditions

  • there was no evidence that the Oxford-AstraZeneca and Pfizer-BioNTech vaccines differed in their ability to reduce infection rates, despite them leading to slightly different immune response

  • everyone showed at least some response to both vaccines, however, a small percentage of people (approximately 5%) had low responses to both vaccines -- it will be essential to monitor their response to a second vaccination

UK National Statistician Professor Sir Ian Diamond said:

"These incredibly important new findings underline the value of the Coronavirus Infection Survey in precisely monitoring the impact of the UK's highly successful vaccine rollout. We have been expanding our collection of blood samples significantly to provide the best possible data on antibody positivity in the general population. With more than four hundred thousand participants, the survey will remain central to our understanding of how people are being protected by the vaccines in the months to come."

Sarah Walker, Professor of Medical Statistics and Epidemiology at the University of Oxford and Chief Investigator and Academic Lead for the COVID-19 Infection Survey, said:

"We don't yet know exactly how much of an antibody response, and for how long, is needed to protect people against getting COVID-19 in the long-term but over the next year, information from the survey should help us to answer these questions. We are very grateful to all our participants for giving up their time to help us."

The Oxford studies are available.