Impact of Implementing Alternative Human Papillomavirus (HPV) Vaccination Strategies in Kenya: A Modeling Study
Background: Implementation delays reduce population-level effects of evidence-based interventions. We conducted a modeling study to estimate the effect of priority policy decisions on a human papillomavirus (HPV) vaccination program in Kenya. Methods: We used a static cohort model to estimate the health effects and costs of introduction and 1-dose switch delays, switching to nonavalent vaccine (9vHPV), supply disruptions, and various scale-up scenarios. Costs were evaluated from the health system perspective. We estimated cervical cancer cases, deaths, disability-adjusted life-years (DALYs), and program and health care costs. Results: Compared with no vaccination, maintaining current program performance would avert approximately 173,000 (95% UI: 149,000–191,000) cases and 2.7 (2.3–3.0) million DALYs across 2019 to 2100. A gradual scale-up of the current 2-dose quadrivalent vaccine (4vHPV) program would avert an additional 16,000 (14–18,000) cases (9%), increasing to 33,000 (28–37,000) cases (19%) if a multiage catchup is implemented in 2030. Accelerated scale-up of 1-dose bivalent vaccine (2vHPV) would avert 184,000 (164–199,000) cases and 3.0 (2.6–3.2) million DALYs, compared with no vaccination; translating to an additional 11,000 (2–17,000) cases averted (6%) compared with maintaining a 2-dose strategy, but at lower program ($81 million vs $76 million) and treatment costs ($2.09 billion vs $2.07 billion). HPV vaccination introduction in 2015 rather than 2019 would have averted an additional 74,000 (43%) cases. Annual vaccine supply disruptions translates to less than 9,000 (200–16,000) cases (5%) and 212,000 (74–305,000) DALYs averted (7%) compared with a 1-dose strategy. A 1-dose 9vHPV strategy would have more health benefits and save additional treatment costs compared with a 1-dose 2vHPV vaccine. Conclusions: Prompt 1-dose switch and rapid scale-up and adoption of a 9vHPV program should be priority policy decisions for Kenya. Graphical abstract