Impact of switching from a quadrivalent to a nonavalent HPV vaccine on HPV infections and cervical cancer in Colombia: a mathematical modelling study

SummaryBackground In 2022, Colombia reported 13.7 cases of cervical cancer per 100,000 females. Given the persistently low coverage of human papillomavirus (HPV) vaccination among girls (51%), alternative interventions are being considered. We assessed the population-level impact of switching from a quadrivalent to a nonavalent vaccine, as well as increasing vaccination coverage to the World Health Organization's target of 90% (≥1 dose). Methods We developed a dynamic model of carcinogenic HPV transmission and vaccination in the population of Colombia aged 15+ years, stratified by health state, sex, age, sexual activity, and HPV vaccination status, accounting for latency. The model was calibrated to HPV prevalence data from Colombia and all Latin America. We evaluated gender-neutral and girl-only routine one-dose vaccination (Findings Both vaccines reduced age-standardised HPV prevalence, with greater reductions observed at 90% coverage, under a gender-neutral scenario, and with a nonavalent vaccine. Switching to a nonavalent vaccine at current levels could reduce HPV prevalence by 39% (range: 33%–46%) in females by 2100, compared to 8% (range: 1%–17%) when only increasing quadrivalent vaccine coverage to 90% in a gender-neutral vaccination strategy. Only a nonavalent vaccine strategy reduced projected age-standardised cervical cancer incidence rates to below 4 cases per 100,000 females as early as 2058. Interpretation Switching to a nonavalent vaccine will accelerate the reduction of HPV infections, thereby expediting progress toward cervical cancer elimination. Funding Fonds de recherche du Québec—Santé and the Division of Cancer Epidemiology at McGill University.