CCU051: Unvaccination and under-vaccination against SARS-CoV-2 in the United Kingdom

Project lead:
Angela Wood and Genevieve Cezard, University of Cambridge

The benefits of Covid-19 vaccinations are well-known; they reduce the risk of infection and lower the risk of serious illness or death associated with Covid-19. Evidence in England and Scotland suggests rates of COVID-19 hospitalisation and COVID-19 death are around five times higher in unvaccinated individuals in comparison to fully vaccinated individuals. Therefore, Covid-19 vaccination is key to society’s recovery from the Covid-19 pandemic. However, across the four nations of the UK and despite vaccines being freely available, millions of individuals remain completely unvaccinated or are under-vaccinated (defined as not having had all available doses of the vaccine). The rates of unvaccinated or under-vaccinated individuals vary by nation, age, ethnicity and other demographic characteristics.

We will extend current knowledge by investigating unvaccination and under-vaccination across all four nations of the UK and will harmonise the results to give an overall UK representation.

By using population-wide detailed electronic health records across the four nations, we will estimate how many individuals in the United Kingdom are completely unvaccinated, or who are under-vaccinated.  We will describe the demographic and clinical characteristics of those who are unvaccinated and under-vaccinated. We will further our understanding by characterising serious outcomes (COVID-19 related hospitalisations, critical care unit admission and death) among unvaccinated and under-vaccinated people in the UK.

We will provide insights for governments and national public health agencies to help improve vaccine uptake and coverage to as many people in the UK as possible. Our proposed work will feed into public messaging that will highly likely save lives, reduce hospitalisation and morbidity, particularly for the most vulnerable members of society.


Undervaccination and severe COVID-19 outcomes: meta-analysis of national cohort studies in England, Northern Ireland, Scotland, and Wales

  • The Lancet publication 15/01/24 can be viewed here
  • Code and phenotypes used to produce this paper are available in GitHub here