Re: The effect of vaccination against human papillomavirus on fecundability

Abstract

Background The human papillomavirus (HPV) vaccine was developed to prevent infection with strains of HPV that cause cervical cancer. While HPV infection has been associated with reduced semen quality and lower pregnancy rates in some studies, no studies have examined the relationship between HPV vaccination and fecundability. We hypothesize that HPV prevention via vaccination will protect fecundity. Methods We analysed data from Pregnancy Study Online (PRESTO), a preconception cohort of North American pregnancy planners. Between 2013 and 2017, we followed 3483 female pregnancy planners and 1022 of their male partners for 12 months or until reported pregnancy, whichever came first. At baseline, participants reported whether they had been vaccinated against HPV and their age at vaccination. We estimated fecundability ratios (FR) and 95% confidence intervals (CI) using proportional probabilities models adjusted for sociodemographics, smoking, and abnormal Pap test before HPV vaccination (females only). Results HPV vaccination was more prevalent among females (33.9%) than males (5.2%). There was little overall association between female vaccination (FR 0.98, 95% CI 0.90, 1.08) or male vaccination (FR 1.07, 95% CI 0.79, 1.46) and fecundability. Among females with a history of sexually transmitted infections or pelvic inflammatory disease (i.e. a group at high risk of exposure to HPV infection), those vaccinated against HPV had higher fecundability than those not vaccinated (FR 1.35, 95% CI 0.99, 1.86). Conclusion Although HPV vaccination had little effect on fecundability overall, HPV vaccination was positively associated with fecundability among women with a history of sexually transmitted infections.