Effectiveness of HPV vaccines against genital warts in women from Valencia, Spain

Abstract

Objectives: To assess the effectiveness of the HPV vaccines in preventing genital warts in young women.

Design: Population-based study using health databases.

Setting: Valencian Community (Spain).

Participants: All girls and women aged 14-19years who were registered in the Valencian Community between January 2009 and December 2014 (n=279,787).

Main outcome measures: Incident cases of genital warts were defined as the first activation of diagnosis code ICD-9-CM 078.11 (Condyloma acuminatum) in primary care and outpatient clinics during the study period.

Results: There were 612 cases of genital warts. The overall incidence rate was 75.8/100,000 person-years (95% CrI 69.7-81.8). There was a decrease in genital warts when female candidates to be vaccinated with quadrivalent HPV vaccine reached the age of 18 (in 2012), compared to previous years. Incidence of genital warts in unvaccinated women and those who received the bivalent vaccine was higher than in girls and women who received the quadrivalent HPV vaccine. The effectiveness of a three-dose regimen of the quadrivalent HPV vaccine was 77% (95 CrI: 66-85%), whereas that of a single dose was 61% (95 CrI: 20-87%). No effectiveness was seen with a full vaccination course with the bivalent HPV vaccine.

Conclusions: Three doses of the quadrivalent HPV vaccine were effective against genital warts in our population. Moreover, with low vaccine coverage the incidence of genital warts decreased only in the vaccinated.

Keywords: Condyloma acuminatum; Genital warts; HPV; HPV vaccine; Human papillomavirus.