BackgroundDespite early success in COVID-19 vaccine rollout, several East Asian countries have seen declining uptake of annual COVID-19 vaccination among adults since 2022. Through a comparative lens, we examine vaccine confidence, trusted information sources, and mRNA vaccine acceptance in four super-ageing societies. MethodsWe analysed nationally representative Global Listening Project survey data from Japan, South Korea, Taiwan, and Hong Kong (2023; n=1,000 participants per region) and a Tokyo deep-dive survey (2024; n=5,050). We compared institutional trust, trusted voices, vaccine safety and perceptions, and mRNA awareness and mRNA vaccine acceptance across demographic groups. We pair descriptive results with contemporary vaccination policy contexts. FindingsA high-uptake/low-confidence paradox emerged around COVID-19 vaccination uptake, exceeding 80% across settings, while confidence in vaccine safety ranged from 51% in Japan to 68% in Taiwan. Consistent gender and generational divides exist: men and older adults’ express higher confidence than women and younger groups. Family members, doctors, and local governments were widely trusted while national governments less so. Older adults relied on television, and younger groups turned to social media for trusted information. Knowledge of mRNA vaccines was limited, even among healthcare professionals. Acceptance of a new mRNA vaccine was highest in Taiwan (78%) and lowest in Japan (56%), with men more accepting than women. InterpretationsTailored communication that leverages local trust networks, addresses cultural, gender-specific concerns and accounts for the influential role of family members and doctors, is essential to build vaccine confidence in routine vaccine programs as well as for pandemic preparedness. Policies should reinforce recommendations and reminder systems (e.g., SMS recall), while simultaneously addressing cost and access barriers for older adults. Integrating gender- and age-specific trust-building measures into immunisation policy and crisis planning is needed.