HPV types 6 /11 can cause recurrent respiratory papillomatosis (RRP), a rare disease with likely mother to child transmission. This exploratory analysis was conducted to characterize the level of HPV types 6/11 antibodies in peripartum maternal blood and in cord blood of infants born to women who received 9-valent HPV (types 6/11/16/18/31/33/45/52/58) (9vHPV) vaccine in the pivotal efficacy study of the 9vHPV vaccine (V503-001, NCT 00543543). Immunization with the 9vHPV vaccine has been shown to elicit marked antibody responses to all 9 vaccine types; however limited data exist on the maternal transfer of anti HPV antibodies.
The overall efficacy study enrolled over 14,000 subjects who were randomized to 9vHPV vaccine or quadrivalent HPV (qHPV) vaccine. Participation in the sub study to assess mother to infant HPV antibody transfer was voluntary. The analysis included all mothers and infants for whom valid results for maternal blood and infant cord blood samples were available at the time of delivery. A total of 20 mother-infant pairs for HPV 6 (n=9; 9vHPV group and n=11; qHPV group) and 21 mother –infant pairs for HPV 11(n=9; 9vHPV group; n=12; qHPV group) were analyzed. Geometric mean titers (GMTs) and seropositivity rates of anti-HPV 6 /11 neutralizing antibodies in the mother-infant pair samples were assessed using competitive Luminex immunoassay.
All mothers and all infants were seropositive for HPV 6 and HPV 11. Anti-HPV 6/ 11 GMTs in peripartum maternal blood and infant cord blood were highly correlated. The GMT ratios of peripartum maternal blood vs. those in cord blood were 1.23 (95% C.I.; 0.43, 3.49) for HPV 6 and 1.29 (95% C.I.; 0.54, 3.07) for HPV 11 in the 9v HPV group and 1.33 (95% C.I.; 0.41, 4.29 for HPV 6 and 1.19 (95% C.I.; 0.45, 3.13) for HPV 11 in the qHPV group, respectively.
These results indicate that antibodies induced by the 9vHPV vaccine cross the placenta and could potentially protect newborns against acquisition of vaccine type HPV related disease, such as RRP. These results mirror similar observations previously made with qHPV vaccine.