Global policy determinants of national human papillomavirus vaccine introductions in 2006–2025

This peer-reviewed article examines how major global policy changes and events were associated with national human papillomavirus (HPV) vaccine introductions in low- and middle-income countries (LMICs) between 2006 and 2025. The study uses generalized linear models (GLMs) to assess the association between predefined policy events and HPV vaccine introduction rates, alongside changepoint analysis to identify shifts in introduction trends without prespecifying when they occurred.

Key findings and insights

• Of four events modelled, WHO’s 2022 recommendation allowing a one-dose HPV schedule was the only one significantly associated with higher LMIC introduction rates (+16.86%, p<0.001).
• Of the estimated 10.79% rise in the LMIC HPV vaccine introduction rate between 2021 and 2022, 10.70% were linked to the one-dose recommendation and only 0.09 to the easing of COVID-19.
• In a counterfactual simulation in which the one-dose recommendation did not occur and the two-dose schedule continued through 2025, the model estimated 18.31 country introductions during 2022–2025, compared with 40.77 in the observed scenario. This corresponds to an estimated 22.46 additional national introductions under the observed one-dose scenario.
• Changepoint analysis identified several shifts in LMIC HPV vaccine introduction trends: a moderate increase in 2013, a sharp acceleration in 2019, a decline in 2020, a rebound in 2022, a decline in 2024, and a renewed increase in 2025. Over this period, the mean annual introduction rate rose from 1.28% in 2006–2012 to 15.70% in 2022–2023 and 28.57% in 2025.
• Results were generally robust across several sensitivity analyses. The one-dose recommendation remained significantly associated with introduction when considering global and high-income-country data, target population size rather than country introductions, countries with lower health expenditure, countries with higher cervical cancer burden, and countries that had never been eligible for Gavi support. However, the authors emphasize that the observational design cannot establish causality and that overlapping events, particularly the recovery from COVID-19 and the 2022 WHO recommendation, make it difficult to isolate the independent effect of each event with certainty.

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