Indeed, the efficiency of the transfer of different anti-B. pertussis antigen-specific IgG1s (pertussis toxin (PT), filamentous hemagglutinin (FHA), pertactin (PRN), fimbriae (FIM)) across the placenta was found to be the highest compared with IgG2, 3 and 4, among a mixed cohort of women vaccinated and unvaccinated against pertussis in pregnancy [46]. This evidence concerns the gene F2 and pertussis.