Benefits of catch-up in vaccination against human papillomavirus in medium- and low-income countries

Human papillomavirus (HPV) vaccination of a birth cohort of girls in the 9-13 age range is recommended as a priority, but decreases in HPV vaccine cost may make catch-up of a few additional cohorts more attractive not only in high-income countries. We assessed the reduction in HPV16 and 18 infections that could be achieved in a medium- (Poland) and a low-income (Guinea) country by adding one-time catch-up of 12- to 19-year-old girls to the vaccination of 11-year-old girls. According to our ad hoc adapted dynamic model of HPV infection transmission, the addition of catch-up was estimated to bring forward the 50% reduction of HPV16/18 prevalence due to vaccination in women 35 by as much as 5 years. Catch-up of 12- to 15-year olds reduced the cumulative probability of HPV16/18 infections by age 35 in the relevant cohorts by about 30% in both countries. Catch-up of 16- to 19-year-old girls added little. Regardless of the chosen catch-up strategy, 16 to 20% of HPV16/18 prevention from vaccination was attributable to herd immunity. Assuming a sufficiently low vaccine cost, the addition of a catch-up round is, therefore, worth considering in medium/low-income countries to extend vaccine benefits to less young adolescent girls whose future access to cervical screening is uncertain. What's new? To prevent cervical cancer, the WHO recommends that girls between the ages of 9-13 years be vaccinated against human papillomavirus (HPV). In this study, the authors asked whether vaccinating older girls (12-15 years) as well, in a one-time catch up cohort, would provide enough additional benefit to be worthwhile. They found that this strategy brought forward the 50% reduction of HPV16/18 prevalence by as much as 5 years, in both a low-income and a medium-income country. As the cost of HPV vaccine decreases, this strategy may thus become desirable especially in low-income countries.