A significant decrease in anogenital warts incidence following the implementation of a national human papillomavirus...

Israel's National Immunization Program (NIP) for human papillomavirus (HPV) began in 2013 for 13-year-old girls with the 2-valent vaccine (2vHPV), switched to the 4-valent vaccine (4vHPV) in 2014, expanded to a gender-neutral (GNV) program in 2015, and adopted the 9-valent vaccine (9vHPV) in 2019. Both 4v- and 9vHPV vaccines protect against HPV types 6 and 11, which cause over 95% of anogenital warts (AGW). This study examined the incidence of AGW following Israel's HPV-NIP.

This retrospective study used de-identified data from Maccabi Healthcare Services (MHS) to examine AGW incidence among individuals aged 10-65 years from 2006 to 2022, stratified by sex, age group, and birth cohort. Poisson regression was employed to compare incidence across pre-NIP (2006-2008), peri-GNV (2014-2016), and post-GNV (2016-2022) periods. Chlamydia and gonorrhea incidence rates served as negative control outcomes for possible changes in sexual behavior.

AGW incidence declined by 64%, 65%, and 37% from pre-NIP to post-GNV period among females aged 10-14,15-17, and 18-21, respectively, while slightly increasing among women aged 45-65. Among males, incidence decreased by 60% and 45% in the 10-14 and 15-17 age groups, respectively, with a delayed decline among 18-21-year-olds as vaccinated cohorts aged in. However, among men aged >21, ineligible for the NIP, AGW incidence increased, mirroring a rise in chlamydia and gonorrhea incidence. Moreover, a gradual post-NIP decline in AGW incidence was observed across NIP-eligible one-year age groups. While AGW incidence increased with age across all cohorts, the increase was less pronounced among vaccine-eligible cohorts.

AGW incidence significantly declined following NIP implementation. However, the increase in AGW incidence among NIP-ineligible adults emphasizes the need to improve vaccination access beyond adolescent NIP.