Current COVID-19 vaccine studies
The UK is a leading force in the development of vaccines for COVID-19. Search our database of studies and trials currently under way.
This is a single-blind trial to determine whether having doses of two different types of COVID-19 vaccines gives as good an immune system response as having two doses of the same vaccine. Adults aged 50 years and above who have already had one dose of COVID-19 vaccine (AstraZeneca or Pfizer) through the NHS rollout programme are recruited to the trial. Participants received their second dose through the trial. Participants were allocated at random and received either:
Participants were asked to complete an electronic diary for up to three months after vaccination in order to record any symptoms or medical conditions.
The last visit (D294) of the trial has been brought forward to accommodate the third dose currently offered by NHS. All study visits were completed in January 2022.
UK Vaccine Task Force (VTF), National Institute Health Research (NIHR), Collaboration for Epidemic Preparedness (CEPI), Novavax (Vaccine supply)