Tongan caregivers trust health workers. Only 41.5% ever got a vaccine recommendation.

Tonga runs what the researchers who studied it describe as an excellent routine immunisation programme. HPV vaccine coverage there has nonetheless remained consistently low after a decade of programming [s1]. A mixed-methods study published in Vaccine set out to establish why, and the answer that came back first was not hesitancy.

The study

Small Pacific Island nations sustain a disproportionate cervical cancer burden [s1] — the disease HPV vaccination is designed to prevent. The study was conducted in August 2025 across all five main island groups of Tonga, enrolling 398 caregivers of girls aged 9 to 14 through stratified multistage cluster sampling [s1].

Two methods ran alongside each other. Quantitatively, multivariable logistic regression identified independent predictors of uptake using the World Health Organization's Behavioural and Social Drivers (BeSD) framework, reported as adjusted odds ratios [s1]. Qualitatively, the team ran 25 Talanoa sessions with purposively sampled key informants [s1]. Talanoa is a traditional Pacific approach to inclusive dialogue, and using it rather than a standard focus group protocol is a methodological choice with consequences — it changes who speaks, in what order, and what can be said.

What predicted vaccination

Six BeSD-aligned predictors independently predicted uptake [s1]. In order of effect size:

Knowing the vaccine was free made the biggest difference, at an adjusted odds ratio of 3.21 (95% CI 2.05–5.02; p < 0.001) [s1]. The authors read this as indicating a communication gap regarding cost [s1].

HPV awareness followed at aOR 2.85 (p < 0.001), then trust in health workers at aOR 2.41 (p < 0.001), concern about cervical cancer at aOR 2.17, social responsibility at aOR 1.94, and ease of access at aOR 1.76 [s1].

The ranking is the finding. In a programme where the vaccine is already free, the strongest predictor of a child receiving it was whether her caregiver knew that. That is not vaccine hesitancy, not a safety concern, and not a supply problem. It is an information failure about price in a system that had already solved price.

The recommendation gap

The number that most directly names a fixable problem sits at the end of the paper. Trust in health workers was high — 87.9% of caregivers reported it — but only 41.5% reported having received a provider recommendation [s1]. The authors identify this as a gap that targeted training could address [s1].

Set those two figures side by side and the shape of the problem is clear. Roughly nine in ten caregivers trusted the person who would deliver the recommendation. Fewer than half got one. The trust that vaccination programmes elsewhere spend years trying to build already exists in Tonga; the conversation that would convert it into a vaccination largely was not happening.

What the Talanoa sessions surfaced

The qualitative arm identified three themes that the regression could not have found [s1].

The first was gendered household decision-making requiring approval from husbands or elders [s1] — meaning the caregiver interviewed may not be the person who decides, and a communication strategy aimed only at mothers may be aimed at the wrong person.

The second was school-based consent procedures that felt rushed or semi-coercive [s1]. This one cuts against the intuition that school delivery is straightforwardly good for coverage. A consent process experienced as pressured can generate refusal, and can damage the trust the programme depends on next year.

The third was the decisive gatekeeping role of religious and community leaders [s1] — a factor that sits entirely outside the health system and cannot be addressed by health service changes alone.

What the study establishes, and what it does not

This is a cross-sectional study in a single country at a single point in time, enrolling caregivers rather than the girls themselves, with vaccination status as reported by caregivers [s1]. It identifies predictors of uptake; it does not test any intervention, and no intervention results are reported. Whether telling caregivers the vaccine is free would actually raise coverage is a plausible inference from the association, not a demonstrated effect.

The authors are also careful about the framework itself, concluding that the BeSD framework is useful in Pacific Island settings with substantial contextual adaptation [s1]. That qualifier is doing real work: a WHO instrument developed for general use required adaptation to produce meaningful results here, and the Talanoa themes — household gender dynamics, faith leader gatekeeping — are precisely the material that the unadapted quantitative instrument did not capture.

What the authors recommend

Their conclusion is that greater coverage gains require improving provider recommendation practices, clarifying vaccine cost and purpose, institutionalising school-based consent processes, and strategic engagement of community and faith leaders [s1].

None of those is a new vaccine, a new supply chain, or a new budget line. All four are changes to how an existing programme communicates — which is a more tractable set of problems than most coverage gaps present, and a reminder that a decade of low uptake is not automatically evidence of resistance to the vaccine itself.

Sources

• [s1] Behavioural and social drivers of HPV vaccine uptake in Tonga: a mixed-methods study using the WHO BeSD framework and Talanoa in a Pacific Island setting, Vaccine, available online 17 June 2026. https://doi.org/10.1016/j.vaccine.2026.128843