Protection to Self and to One's Sexual Partner After Human Papillomavirus Vaccination: Preliminary Analysis From the Transmission Reduction And Prevention with HPV Vaccination Study.

BACKGROUND: It is unknown whether recently human papillomavirus (HPV)-vaccinated individuals confer protection against vaccine-preventable HPV types to their partners. METHODS: Participants 18 to 45 years old who were living in Montreal, Canada, and in a heterosexual relationship of 6 months or less were randomly assigned to receive the intervention HPV vaccine, Gardasil or Gardasil 9, or active control (AC), Avaxim, a hepatitis A vaccine. Couples attended a maximum of 6 clinic visits (baseline and at 2, 4, 6, 9, and 12 months) and provided genital samples for detection of 36 HPV genotypes. Participants were vaccinated at baseline and at 2 and 6 months. We used Cox proportional hazards regression models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between the administered vaccine and infections at the HPV episode level. RESULTS: We restricted analyses to 273 participants (intervention: n = 141, AC: n = 132) who had at least 2 visits with valid HPV data. The HR of becoming positive for a given vaccine-preventable HPV type in the intervention group among those who received at least 1 dose compared with AC was 0.47 (95% CI, 0.23-0.97). Comparing individuals with HPV-vaccinated versus AC-vaccinated partners, there was no difference in risk of becoming positive for a given vaccine-preventable HPV type among those whose partners received at least 1 (HR, 1.46; 95% CI, 0.73-2.94) or 2 (HR, 0.78; 95% CI, 0.31-1.96) doses. CONCLUSIONS: Our study provides inconclusive evidence that individuals whose partner recently received an HPV vaccine are protected from vaccine-preventable types but demonstrates that vaccinated individuals are at a lower risk of incident infections.Trial Registration Number: NCT01824537.