Human papillomavirus vaccination may be associated with sharp reductions in vaccine-type infections among adolescent females and young women over 17 years. Vaccinated patients showed declines of 98% for HPV-16/18, 94% for HPV-6/11/16/18, and 76% for the nine-valent group. Unvaccinated patients also had decreases, with HPV-16/18 falling 72% and HPV-6/11/16/18 falling 76%, consistent with herd protection. Vaccine coverage increased from none in 2006 to 82% by 2023. The adjusted odds of detecting vaccine-type HPV were lower across all groups, including 0.03 for HPV-16/18, 0.06 for HPV-6/11/16/18, and 0.22 for nine-valent types.
The study included 2,335 sexually experienced patients aged 13 to 26 years across six survey waves conducted from 2006 to 2023. Recruitment occurred at a Teen Health Center and public clinics. Vaccination status was confirmed through electronic health records and a state immunization registry. HPV detection used Roche Linear Array in earlier waves and TypeSeq2 in later waves. Propensity score weighting and logistic regression were applied to address differences in participant characteristics across survey years.
The mean age was 19 years. Most patients identified as African American (65%), with 25% identifying as White and 7% as Hispanic. More than half reported a history of sexually transmitted infection, and nearly 80% reported two or more lifetime male partners. Among vaccinated patients, 71% received only the quadrivalent vaccine, while 29% received at least one dose of the nine-valent vaccine. By 2021 to 2023, nearly 78% of vaccinated patients had received the nine-valent vaccine.
The decreasing number of unvaccinated patients in later waves limited precision for herd-effect estimates. Because the study was conducted in a single region, findings may not be generalizable to broader populations. The change in HPV genotyping assays during the study could have introduced variation in type detection. Overlap between quadrivalent and nine-valent vaccine recipients made it difficult to isolate the effects of each vaccine, and possible cross-protection may have influenced outcomes.
17 years after HPV vaccine introduction, large reductions in vaccine-type infections were observed among vaccinated patients and declines among unvaccinated patients indicated herd protection. High vaccination coverage was associated with these population-level benefits. Continued monitoring was recommended to assess long-term effectiveness and coverage.
There should be no complacency in our sustained efforts; rather, as the scientific community, we should be encouraged to scale up vaccination-related programming and continue to monitor population-level HPV vaccination rates and effects,” wrote Teresa A. Imburgia, MD, and Rachel A. Katzenellenbogen, MD, of the Department of Pediatrics at the University of Washington and Seattle Children’s Research Institute.
The study reported no relevant conflicts of interest.
Source: JAMA Pediatrics and Editorial