Human papillomavirus infection and vaccination among young females in rural Uganda.

Cervical cancer is the most common cancer in Uganda. In 2015, a national human papillomavirus (HPV) vaccination program was initiated, targeting girls aged 10 years. To provide a pre-vaccination baseline to monitor HPV vaccine effectiveness, first-void urine (FVU) samples were collected from females aged 16-21 years in the General Population Cohort (GPC) in South-East Uganda, between 2019 and 2023. HPV vaccination status was obtained from questionnaires and vaccination cards. FVU samples were tested for 28 HPV types using Allplex HPV28. Among 1009 participants, 28 type prevalence was 33%, and was higher among females reporting sexual intercourse (aPR = 3.7, 95%CI 2.8-4.8) and HIV infection (PR = 1.4, 95%CI 1.1-1.8). HPV16/18 prevalence was 4.8% overall, and lower in 146 vaccinated (1.4%) than 783 unvaccinated (5.6%) females (aPR = 0.4, 95%CI 0.1-1.4). No decrease was observed in other high-risk (aPR = 1.5, 95%CIs 1.0-2.2) or low-risk (aPR = 1.4, 95%CIs 1.0-2.1) types which were more prevalent in vaccinated females. Among vaccinated 16-21 year-olds, 30.8% (n = 45) received one, 44.5% (n = 65) two, and 14.3% (n = 21) three doses. Vaccination status was also obtained from 1121 younger girls aged 10-15 years from the same GPC population, among whom 42.8% (n = 480) were vaccinated, 47.1% (n = 226) with one, 44.2% (n = 212) two, and 6.7% (n = 32) three doses. In conclusion, we report high HPV prevalence in young women in Uganda and see first impacts of vaccination on HPV16/18 infection. This population, shown to have suboptimal HPV vaccine coverage and heterogeneity in doses received, can serve as a robust baseline for future evaluations of HPV vaccine effectiveness.