Long-term effectiveness of at least one dose of human papillomavirus vaccine in adolescents: A test-negative case–control study

OBJECTIVES: Human papillomavirus (HPV) vaccination has been recommended by the World Health Organization as part of the cervical cancer elimination strategy. Many countries have introduced single-dose or two-dose vaccination schedules. However, data on the effectiveness of at least one dose of the HPV vaccine among school-aged girls remain limited. METHODS: The study was a test-negative case-control conducted to estimate the effectiveness of HPV vaccines (VE) against high-risk types of HPV among adolescents in a real-world setting. Demographics and risk factors data were collected. Cases were adolescent who tested positive for high-risk HPV DNA. Time-matched controls were those who tested negative. RESULTS: Overall, 760 participants with a mean (SD) age of 18.2 (2.9) years underwent for HPV DNA testing. Among 114 vaccinated participants, 34 had received one dose and 80 had received two doses; the mean (SD) time since vaccination was 65.89 (23.67) months. A total of 100 participants tested positive for high-risk HPV types. The four most common high-risk types were HPV 16, 59, 52, and 58. The overall adjusted VE against high-risk HPV types among young women with a duration of >5 years was 91.0% (95% confidence interval: 33.4-98.8). The VEs against HPV high-risk infection among the age groups 9-18, 9-15, and 9-12 years who had received at least one dose were similar for >5 years. CONCLUSION: At least one dose of the HPV vaccine was shown to be highly effective in preventing high-risk HPV types for >5 years across vaccination age up to 18 years.