Characterisation of immune responses to vaccination against SARS-CoV-2

COVID-19 is an infection caused by a virus that first emerged at the end of 2019 and has since been declared a global pandemic. Multiple vaccines have been in development globally including three vaccines that have now been approved for use in the UK. At Imperial College London a novel self-amplifying RNA (saRNA) vaccine has been developed and is being used as part of a clinical trial since June 2020 (COVAC1). Those who have already had a natural SARS- CoV-2 infection are likely to have some protection against further infection, although reports of re-infection do exist. It is not clear how long such protection would last and so it is important to understand how a vaccine may boost the immune response in these individuals. In order to explore this, I plan to look at immune responses up to one year post vaccination against SARS- CoV-2 using both the Imperial saRNA vaccine and the Pfizer/BioNTech mRNA vaccine in individuals who have recovered from natural infection compared to those who have never previously been infected. This will provide important information on how the immune system behaves after vaccination in those with pre-existing antibodies, and will help to inform further vaccination strategies and research.