Understanding the key determinants of an HPV therapeutic vaccine: a modeling analysis

Despite incredibly effective tools to prevent HPV infection and treat precancerous lesions, the scale-up of existing interventions in most low and middle-income countries has been slow, leaving a residual burden of invasive cervical cancer that will persist for decades. An HPV therapeutic vaccine may overcome some of the scalability and infrastructure challenges of traditional screening and treatment programs, though its potential public health value depends upon its characteristics, delivery strategy, and the underlying immunity of the population on which it would act. This analysis uses HPVsim, an open-access agent-based simulation framework, to evaluate the impact of a range of potential HPV therapeutic vaccines with varying scale-up of existing preventive interventions in nine high-burden low- and middle-income countries (LMICs). For each setting, the model is populated with context-specific demographic and behavioral data, and calibrated to fit estimates of HPV and cervical disease by age. We find that an HPV therapeutic vaccine that clears 90% of virus and regresses 50% of high-grade lesions, reaching 70 percent of 35-45 year old women starting in 2030, could avert 1.2-2.2 million incident cases of cervical cancer, 500,000-1.2 million cervical cancer deaths and 20-40 million disability adjusted life years (DALYs) in the modeled high-burden LMICs over 30 years. The size of the impact is sensitive to rates of background intervention scale-up and the characteristics of the vaccine, including ability to establish long-lasting immune memory.