Modeling the health and economic implications of adopting a 1-dose 9-valent human papillomavirus vaccination program in adolescents in low/middle-income countries: An analysis of Indonesia

Background Recent evidence suggests that 1 dose of the human papillomavirus (HPV) vaccine may have similar effectiveness in reducing HPV infection risk compared to 2 or 3 doses. Objective To evaluate the public health impact and cost-effectiveness of implementing a 1-dose or a 2-dose program of the 9-valent HPV vaccine in a low- and middle-income country (LMIC). Methods We adapted a dynamic transmission model to the Indonesia setting, and conducted a probabilistic sensitivity analysis using distributions reflecting the uncertainty in levels and durability of protection of a 1-dose that were estimated under a Bayesian framework incorporating 3-year vaccine efficacy data from the KEN SHE trial (base-case) and 10 year effectiveness data from the India IARC study (alternative analysis). Scenarios included different coverage levels targeted at girls-only, or girls and boys. Costs and benefits were computed over 100 years from a national single-payer perspective. Results Depending on the coverage and target population, the median number of cancer cases avoided in 2-dose programs ranged between 600,000–2,100,000, compared to 200,000–600,000 in 1-dose programs. The 1-dose programs are unlikely to be cost-effective compared to 2-dose programs even at low willingness-to-pay (WTP) thresholds. The girls-only 2-dose program tends to be cost-effective at lower WTP thresholds, particularly in scenarios with high coverage, dose price and discount rate, while the girls and boys 2-dose program is cost-effective at higher WTP thresholds. In the alternative analysis, 1-dose programs have higher probability of being cost-effective compared to the base-case, particularly for low WTP thresholds (less than 0.5 GDP) and for high coverage, dose price and discount rate. Conclusion Adoption of 1-dose programs with 9-valent vaccine in an LMIC resulted in more vaccine-preventable HPV-related cancer cases than 2-dose programs. The 2-dose programs were more likely to be cost-effective than 1-dose programs for a wide range of WTP thresholds and scenarios. © 2024 Daniels et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.