Vaccine Breakthrough Project

Project summary:

Vaccine breakthrough is a term used to describe the SARS-CoV-2 virus ‘breaking through’ the protection given by COVID-19 vaccines. This includes first-time infections, reinfections and COVID-19 related hospitalisations and deaths. The project is focusing on these two types of breakthrough as they are both of serious concern.

The Vaccine Breakthrough Project is investigating breakthroughs that happen after a person is given either their third or booster dose vaccinations. This includes:

  • Examining how often breakthroughs occur in the UK
  • Identifying factors that put a person at greater risk of experiencing a serious breakthrough event (e.g. their health history, demographic characteristics
  • Assessing how these risks may differ depending on the number of doses a person receives, the type of vaccine they are given, and what variant dominates at the time of infection  

Our research will allow us to understand who is most at risk of experiencing a breakthrough event, and later inform UK policy makers and healthcare services on who is the most likely to benefit from further rounds of vaccination, new treatments (e.g., monoclonal antibodies) and non-clinical interventions (e.g., shielding).

To accomplish this, we are building on work previously done by the HDR UK-National Core Studies funded DaC-VaP project, which looked at the real-world effectiveness of first and second-dose vaccines.

We are also examining data from the ongoing, MRC and Scottish Government funded, EAVE II project which continues to track the pandemic and monitor its effects across Scotland. Its cohort includes data on vaccination status, primary care, secondary care, laboratory tests (e.g., Real-Time Polymerase Chain Reaction (RT-PCR)), viral antibodies, viral variants and mortality.

Our project also expanding to include data sourced from other UK nations, such as SAIL Databank in Wales, Honest Broker Service in Northern Ireland and Office for National Statistics in England.


National Core Studies Immunity Programme, UK Research and Innovation (Medical Research Council), Scottish Government, Health Data Research UK, Chief Scientist Office, National Institute for Health Research

Leader researcher:

Professor Aziz Sheikh

Lead institution:

Usher Institute, University of Edinburgh

Vaccine type: