Factors, motivations and barriers associated with eagerness to volunteer in COVID-19 vaccine clinical trials in France: A mixed-method study.

INTRODUCTION: During the COVID-19 pandemic, there was an unprecedented effort to engage people in clinical vaccine research. Most of the French volunteers registered in the first weeks after the launch in October 2020 of COVIREIVAC, an electronic platform dedicated to COVID-19 vaccine clinical trials (VCT). In the context of pandemic preparedness, identifying factors associated with eagerness or hesitancy to participate in VCT may help to increase recruitment of volunteers from diverse backgrounds. METHODS: We used a mixed-method survey offered to the volunteers registered on the COVIREIVAC platform, and semi-directed interviews in participants to COVID-19 VCTs. Volunteers were divided into three categories: early volunteers (EV), registered before the launch of the COVID-19 vaccination campaign, middle volunteers (MV) registered between the first of January 2021 and the generalization of the COVID-19 vaccination to the entire population in May 2021, and late volunteers (LV) registered afterward. RESULTS: Among the 56,101 COVIREIVAC registered volunteers, 2,741 (4.9 %) completed the survey, 1,915 (69.6%) were EV, 301 (11.0%) were MV and 525 (19.2 %) were LV. Sixteen were face-to-face interviewed. Age, educational level, attitudes toward vaccination evaluated with the 5C-model did not differ between EV and MV. Women gender and the possibility to choose the vaccine platform was associated with being a MV. LV were significantly younger, had a lower educational level and had less positive attitudes toward vaccines than EV and MV. The main motivations for participation in VCTs were altruistic notably in EV and MV. For LV, they registered in the hope to choice the vaccine technology. Among the respondents, 2,041 (74.5 %) would consider to participate in a non-COVID-19 VCT. CONCLUSION: LV on the COVIREIVAC platform had a distinct profile from EV and MV, and were less confident in vaccines. Restoring confidence in vaccines and clinical may help to engage more diverse populations in VCTs.

A national platform for Covid-19 vaccine studies recruitment in France: Covireivac volunteer's characteristics.

During the Covid-19 pandemic, the urgent need for safe and effective vaccines has led to many vaccine trials, implying fast and extensive recruitment of volunteers. In France, until 2020, vaccine clinical research participants were usually recruited locally, through center-based pools of volunteers, and local communication plans. Covireivac is a French public online platform launched on 10/01/2020 that enables national, large-scale recruitment of volunteers for Covid-19 vaccine studies. On the Covireivac website, all adult participants registered online, gave their informed consent, and filled out two online forms with information on their identity, health status (comorbidities, treatments), and known exposure to SARS-CoV-2. Since July 2021, volunteers could mention if their children are interested in participating in a Covid-19 vaccine trial. The objective of this work is to describe Covireivac's volunteer characteristics registered from 10/01/2020 to 11/02/2022. To identify independent volunteer characteristics associated with a period of registration we performed a multivariate logistic regression. Among 54,424 registrations, 52,391 (96%) were analysed; 61% were male (n = 31,893), median age was 50 y; 13% (n = 6586) were healthcare workers. At registration, 15,879 volunteers (33%) reported at least one comorbidity, among whom 16% (n = 7349) were obese and 17% (n = 8346) had hypertension. Most volunteers registered during the first month (n = 35,876, 66%). The Covireivac platform allowed quick and large recruitment of potential volunteers for Covid-19 vaccine trials and could be used on a larger scale for vaccine trials in France. It could facilitate recruitment in vaccine trials and provide sponsors with better visibility of the recruitment capacities of clinical research centers.