Every year, human papillomavirus (HPV) causes hundreds of thousands of deaths worldwide, mostly from cervical cancer. This is an especially serious problem in low-resource countries, where vaccinating young girls and screening adult women are hard to carry out on a regular basis.
This work builds a mathematical model that describes how the virus spreads through a population, from the moment a healthy person becomes infected, through natural recovery, or, in some women, progression toward disease, taking into account people’s age and sex. The model is first checked to make sure it faithfully reflects what is observed in real life, and it then reveals a central result: there is a critical threshold in prevention efforts. Below this threshold, the outbreak gradually dies out and can disappear; above it, the virus keeps circulating and becomes permanently established in the population.
The model is then used to compare three ways of fighting the disease: vaccinating adolescent girls, screening adult women, and combining both interventions. Using optimization techniques, the study looks for the best way to split a limited budget between these actions. The result is clear: when resources are tight, screening alone is the most cost-effective strategy, since it prevents more infections for a given cost. Combining vaccination and screening remains more effective in terms of total infections avoided, but requires a significantly larger budget.
Finally, the model is made more realistic by accounting for the fact that vaccination and screening campaigns are not carried out continuously over time: they alternate between intensive periods (campaigns) and quieter periods (routine care). The study shows that routine care alone is generally not enough to push the disease back, but that adding periodic campaigns, when frequent and intense enough, can bring the situation back below the elimination threshold. This result highlights the importance of screening in low-resource settings and the decisive role of well-planned campaigns in the long-term goal of eradicating HPV.
