The efficacy of COVID 19 vaccines for reducing the risk of severe COVID-19 infection is demonstrated in real life.~However, data currently available on the persistence of immunity after vaccination on the one hand and the emergence of viral variants with reduced sensibility to vaccine immunity on the other, raise the need to administer boosters to maintain the protection and to compare different strategies as bivalent mRNA vaccines but also others platforms.~The vaccines currently recommended as boosters in France are mRNA bivalent vaccines, adapted to better match the circulating variants of SARS-CoV-2 and expected to provide broader protection against Omicron sub variants (19). However, the rapid antigenic evolution of SARS-CoV-2 and the antigenic imprinting against the initial Hu-1 strain could reduce their effectiveness.~More recently, the Beta-variant recombinant protein booster vaccine (VidPrevtyn Beta, Sanofi) obtained European authorization and is recommended in France as booster as an alternative to the bivalent mRNA vaccines (21, 22). However, in the absence of comparative data with the bivalent mRNA vaccines, VidPrevtyn Beta is recommended as second line.~It has been shown with vectored vaccines that a heterologous vaccination scheme could be more immunogenic than a homologous scheme (23). Our group previously showed that VidPrevtyn Beta, administered as a third vaccine dose, induces higher immune response than the mRNA BNT162b2 vaccine (Comirnaty, BioNTech-Pfizer), against Beta variant but also others variants of concern (VOC) including Omicron BA1 (20) and Omicron BA4/5 (data submitted for publication). The data available at 3 and 6 months after the boost, show that VidPrevtyn Beta could be also of interest in term of durability of the response (data not published). The hypothesis is that a Beta variant protein recombinant vaccine could enlarge the protection against the variants by overpassing antigenic imprinting and the adjuvant improve the duration of immune response and protection. Moreover, the Beta-variant recombinant protein vaccine could bring an advantage in terms of reactogenicity, acceptability, cost and accessibility.~In this context, as recently pointed by the HAS, comparative data on immunogenicity and reactogenicity between a bivalent mRNA vaccine and the Beta-variant recombinant protein, both administered as boosters, are needed to better adapt the COVID 19 vaccine recommendations for the future.~This study is Comparative, non-inferiority, single-blinded, multicenter, randomized trial.~Randomization in a 1:1 ratio, will be stratified by age (18-60 years and ≥ 60 years of age) and history of SARS-CoV-2 infection
The objective of this trial is to compare the immunogenicity and the safety of the Beta-variant recombinant protein booster vaccine (VidPrevtyn® Beta, Sanofi) to a bivalent mRNA vaccine (Comirnaty Original/Omicron BA.4-5, BioNTech-Pfizer) in adults previously vaccinated with at least 3 doses of COVID-19 mRNA vaccine. The results will provide important data for the future COVID 19 vaccine strategy.~A biobank will also be set up to evaluate the protection conferred by one or other of these vaccines as booster in the event of the emergence of new variants in the future.