Behavioural and social drivers of HPV vaccine uptake in Tonga: a mixed-methods study using the WHO BeSD framework and...

Small Pacific Island nations sustain a disproportionate cervical cancer burden. Despite an excellent routine immunization program, HPV vaccine coverage in Tonga remains consistently low after a decade of programming. We used the WHO Behavioural and Social Drivers (BeSD) framework to identify drivers of HPV vaccine uptake among caregivers and to examine the underlying contextual mechanisms shaping vaccination decisions in this Pacific Island setting.

A mixed-methods cross-sectional study was conducted in August 2025 across all five main island groups of Tonga. We enrolled 398 caregivers of girls aged 9-14 years through stratified multistage cluster sampling. Multivariable logistic regression identified independent predictors of HPV vaccination uptake, reported as adjusted odds ratios (aOR) with 95% confidence intervals (CI). We conducted 25 Talanoa sessions, a traditional Pacific approach for inclusive dialogue, with purposively sampled key informants. Findings were analyzed thematically using an inductive-deductive approach.

Six BeSD-aligned predictors independently predicted vaccine uptake. Knowing the vaccine was free made the biggest difference (aOR 3.21, 95% CI 2.05-5.02; p < 0.001), indicating a communication gap regarding cost. Other significant drivers were HPV awareness (aOR 2.85, p < 0.001), trust in health workers (aOR 2.41, p < 0.001), concern about cervical cancer (aOR 2.17), social responsibility (aOR 1.94), and ease of access (aOR 1.76). Talanoa sessions revealed three themes: 1) gendered household decision-making requiring approval from husbands or elders; 2) school-based consent procedures that felt rushed or semi-coercive; and 3) the decisive gatekeeping role of religious and community leaders.

With substantial contextual adaptation, the BeSD framework is useful in Pacific Island settings. Greater coverage gains require improving provider recommendation practices, clarifying vaccine cost and purpose, institutionalizing school-based consent processes, and strategic engagement of community and faith leaders. Despite high trust in health workers (87.9%), only 41.5% of caregivers reported receiving a provider recommendation, a gap that targeted training could address.