Long‐term effectiveness of HPV vaccination against HPV infection in young Japanese women: Real‐world data

In Japan, public funding for HPV vaccination began in 2010 for girls aged 13–16 years (birth cohort years 1994–1997) and women born in 1994 who turned 25 in 2019. We aimed to verify the long‐term effectiveness of the bivalent HPV vaccine in women aged 25 years. Subjects were women aged 25–26 years who underwent cervical cancer screening and HPV testing in Niigata from 2019 to 2020 (birth cohort years 1993–1994). Information on vaccination status and sexual behavior was obtained from a questionnaire and municipal records. We compared the HPV infection rates of the vaccinated and unvaccinated groups. Of the 429 registrants, 150 (35.0%) and 279 (65.0%) were vaccinated and unvaccinated, respectively. The average period from HPV vaccination to HPV testing was 102.7 months (8.6 years), with a median of 103 months (range 92–109 months). The HPV high‐risk infection rate was 21.3% (32/150) in the vaccinated group and 23.7% (66/279) in the unvaccinated group (P = 0.63). The HPV16/18 infection rate was 0% (0/150) in the vaccinated group and 5.4% (15/279) in the unvaccinated group, showing a significant difference (P = 0.0018), and the vaccine effectiveness was 100%. The cross‐protective type HPV31/45/52 infection rate in the vaccinated group was significantly lower than that in the unvaccinated group (3.3% vs. 10.0%, P = 0.013). There was no significant difference in the mean age at sexual debut and the number of previous sexual partners between the two groups. We have demonstrated the long‐term 9‐year effectiveness of the bivalent vaccine against HPV infection for the first time in Japan.