Representation of ethnic and racial minority groups in European vaccine trials: a quantitative analysis of clinical trials registries.

Objectives: The representation of ethnic minority groups in European vaccine trials is an important and hitherto unaddressed gap in the literature. The objectives of this study were to determine the proportion of European vaccine trials that report data on the ethnic demographics of participants, to evaluate the distribution of ethnic minority groups among trial participants (where reported), and ascertain whether this is representative of the wider population of the country. Design: We evaluated the representation of ethnic/racial minority groups in clinical research, conducting a quantitative analysis of clinical trials registry data from completed vaccine trials in Europe that commenced between 1 January 2010 and 31 December 2020. Data sources: Data were collected from four major clinical trial databases: ClinicalTrials.gov, the European Union Clinical Trials Register (EUCTR), the International Standard Randomised Controlled Trial Number (ISRCTN) and the International Clinical Trials Registry Platform (ICTRP). Results: A majority of clinical trials failed to either record or report the race/ethnicity of their volunteers on the clinical trials registry databases. Reported participants in UK vaccine trials were not representative of the ethnic demographics of the wider population. Unavailability of population-level ethnicity data for many European countries was a significant barrier to determining the wider applicability of these findings. Conclusions: Under-representation of ethnic minority groups in vaccine trials may have implications for the effectiveness of routine vaccinations, threatening the principles of justice and equity that are embedded in national medical research guidelines. Unavailability of population-level ethnicity data exacerbates the prevailing lack of understanding of the extent of this issue, despite literature indicating cause for concern.