Covid-19 vaccination in inflammatory conditions treated with immune suppressing drugs: a study of clinical effectiveness and vaccine safety using data from the Clinical Practice Research Datalink (CPRD).

One in fifty people have inflammatory conditions such as rheumatoid arthritis. These conditions result from the immune-system, that usually fights off infections, getting out of control and damaging the joints and other parts of the body. To stop such damage from occurring, people with these conditions take medicines that dampen the immune-system. However, this not only increases their risk of getting very unwell with infections including with Covid-19, but it also means that there may be less benefit from vaccinations. There is also concern among patients that vaccinations may flare-up the inflammatory conditions. This study will answer the following questions: Are vaccines against the novel coronavirus less protective against Covid-19 in immune-suppressed people than in the general population? Is the duration of protection shorter in the immune-suppressed people? Does vaccination against Covid-19 increase the risk of flare-up of the inflammatory condition? We will use routinely collected anonymous information from the care of NHS patients obtained from the Clinical Practice Research Datalink (CPRD)-Aurum. CPRD-Aurum contains data on over 14 million UK residents currently registered with a GP and is linked to hospitalization and death records. We will look at data for two groups of people given the vaccine against Covid-19: Group-A: People with inflammatory conditions treated with immune-suppressing medicines, Group-B: People without inflammatory conditions and not treated with immune-suppressing medicines. Each person from group-B will be matched to one person in group-A for their age, sex, type of Covid-19 vaccine received and date of vaccination. We will follow them up using information in their electronic health records and compare their risk of hospital admission with Covid-19, GP consultation with Covid-19 and death due to Covid-19. Next, we will find out if there is a time after vaccination at which immune-suppressed people seem to stop being protected from Covid-19. Finally, we will compare the rate of getting a flare of the underlying inflammatory condition in the 6-week period after the Covid-19 vaccine to that in the remaining study period. We will involve PPI members in the study and request them to provide their perspectives before starting the study and when interpreting the study findings. They will be involved in disseminating the results and when engaging with health policy makers such as the Joint Committee on Vaccination and Immunisation (JCVI) and national specialist societies. We will share our findings with policymakers with whom we have links. Our study will inform policy around the timing of future Covid-19 booster vaccination in immune-suppressed people. We will share our results with patients and the public. We will disseminate the findings at scientific meetings and in medical journals. We will work with national charities to include key messages emerging from this study in their patient information resources.