Long-term HPV-specific immune response after one versus two and three doses of bivalent HPV vaccination in Dutch girls

Background In view of further reduction of HPV vaccination schedules, gaining more insight into humoral and cellular immune responses after a single HPV vaccine is of great interest. Therefore, these responses were evaluated after different doses of the bivalent (2v) HPV-vaccine in girls. Methods Blood was collected yearly up to seven years post-vaccination with one-, two- or three-doses of the 2vHPV vaccine (N = 890). HPV-type-specific IgG and IgA-antibody levels, IgG-isotypes and avidity indexes were measured by a virus-like-particle-based multiplex-immuno-assay for two vaccine and five non-vaccine HPV types. HPV-type-specific memory B-cell numbers- and T-cell cytokine responses were determined in a subpopulation. Results HPV-type-specific antibody concentrations were significantly lower in one- than in two- and three-dose vaccinated girls but remained stable over seven years. The lower antibody response coincided with reduced HPV-type-specific B- and T-cell responses. There were no differences in both the IgG subtypes and the avidity of the HPV16-specific antibodies between the groups. Conclusions One-dose of the 2vHPV vaccine is immunogenic, but results in less B- and T-cell memory and considerable lower antibody responses when compared with more doses. Therefore, at least of some of girls receiving the one-dose of the vaccination might be at higher risk for waning immunity to HPV in the long-term.