Among the four classifications of the COVID-19 vaccine, the vaccine research with the most interest concerned messenger-RNA (mRNA) vaccines, with 1210 publication documents (63.2%); this was followed by recombinant adenovirus vector vaccines, with 397 publication documents (20.7%), inactivated COVID-19 vaccines, with 231 publication documents (12.1%), and recombinant S proteins subunit vaccines, with 76 publication documents (4.0%). This evidence concerns the gene PROS1 and COVID-19.