Characteristics of Vaccine Champions (N = 27).

There is a global need for effective strategies to improve acceptance and uptake of the human papillomavirus (HPV) vaccine, particularly in the Pacific where cervical screening and treatment options are limited. While the Pacific Island nation of Tonga has high routine childhood vaccine coverage, HPV vaccine uptake has remained low since its introduction in 2022. To improve vaccine acceptance and uptake, recent evidence supports the use of community engagement approaches like the Vaccine Champions program, which trains health and community leaders to advocate for vaccines. We assessed the reach, effectiveness, adoption, implementation, and maintenance of the Vaccine Champions program in Tonga. In March 2023 we conducted a co-design workshop with government and non-government stakeholders to adapt the program and establish key features. Diverse Vaccine Champions were trained in June to run vaccine information sessions in their communities until December 2023. We used the RE-AIM framework to evaluate program implementation and impact through surveys and interviews with co-design participants, Vaccine Champions, and community members. Co-design participants (n = 29) agreed to focus on the HPV vaccine, identified leading barriers and potential Vaccine Champions. We trained 27 Vaccine Champions including teachers, local officials, nurses, and representatives from disability, youth, and sports groups. Most were female (19/27; 70%) and had no health background (25/27; 93%). Training increased Vaccine Champions’ trust and support for vaccines, and confidence to communicate about vaccines. Vaccine Champions ran 57 vaccine information sessions, reaching 1138 community members. Parent or caregiver intention to vaccinate their daughters against HPV increased from 70% to 88% after attending a community session. The Vaccine Champions program is a culturally tailored community engagement approach to increase HPV vaccine acceptance and uptake, supporting global efforts towards cervical cancer elimination. It is continuing in Tonga in 2025 with strong national support. Implementation and evaluation process findings can support program localisation elsewhere.