To calculate the bivalent vaccine effectiveness (VE) against high-risk HPV DNA positivity, using cross-sectional data from the Netherlands up to six years post vaccination.
We included all vaccine-eligible women from the PASSYON study, a biennial cross-sectional survey among 16- to 24-year-old STI-clinic visitors (2009-2015). Vaginal swabs were analyzed using a sensitive PCR-based reverse line blotting system (SPF10-LiPA25) which is able to detect the high-risk types 16/18/31/33/35/39/45/51/52/56/58/59. VE was estimated by a logistic mixed model corrected for demographics and (sexual) risk behavior, with a random intercept to account for residual clustering of HPV types within individuals. HPV DNA positivity was compared between women who reported to be vaccinated at least once and women who reported to be unvaccinated. VE was calculated as (1-adjusted Odds Ratio)*100%.
We included 1087 vaccine-eligible women of the PASSYON study years 2011-2015. Of these women, who were 16- to 22-years-old, 53% tested positive for a high-risk type and 60% reported to be vaccinated. Among women with serum available (43%), the self-reported vaccination status agreed well with the HPV16/18 antibody concentration (AUC 92.3%), suggesting reliable reporting. The pooled VE against the vaccine types HPV16/18 was 89.9% (81.7-94.4); 92.3% (82.5-96.6) against HPV16 and 85.5% (66.0-93.8) against HPV18. Moreover, we calculated significant VE against the non-vaccine types HPV45 (91.0% [59.7-98.0]), HPV35 (57.1% [2.3-81.2]), HPV31 (50.0% [10.8-72.0]) and HPV52 (37.2% [9.2-56.6]). Vaccinated women were more often HPV59 positive (6.0%) than unvaccinated women (3.4%), resulting in a VE of -89.4% (-259.9-0.3). The pooled VE against all high-risk types was 32.9% (20.2-43.7).
We demonstrate a high VE against prevalent infection with the bivalent vaccine types. In addition, we found significant cross-protection against HPV types 45, 35, 31 and 52. The negative VE against HPV59 is notable and needs further investigation.