CHMP5 and COVID-19: When comparing the spike-specific immune responses elicited by mRNA based-vaccines with other COVID-19 licensed vaccine formulations, such as Adenovirus-vectored vaccines (Ad26.COV2.S or ChAdOx1-S) and the recombinant spike protein vaccine (NVX-CoV2373) [31,71], mRNA vaccines were consistently the most immunogenic, both in terms of spike-specific IgG and B cells.