Bridging Economics and Public Trust: A Study of Dengue Vaccine Cost-effectiveness and Acceptance in Thais Visiting Hospital

Study 1: Cost-effectiveness of TAK-003 Dengue Vaccination in Thailand

This study aims to evaluate the cost-effectiveness of introducing the live-attenuated tetravalent dengue vaccine (TAK-003) into Thailand's national immunization program. The study will compare routine vaccination strategies targeting two high-risk age groups: older children aged 9-14 years and adolescents/young adults aged 15-24 years, to identify the most appropriate target population for national implementation.

A model-based economic evaluation will be conducted using a static Markov model combined with a decision tree from a societal perspective. Model parameters will be obtained from published literature, national surveillance databases, healthcare utilization data, and other relevant sources. The model will estimate lifetime health outcomes, healthcare costs, quality-adjusted life years (QALYs), incremental cost-effectiveness ratios (ICERs), and budget impact. Deterministic and probabilistic sensitivity analyses will be performed to assess uncertainty in model parameters.

The findings are expected to provide evidence to support policy decisions regarding the inclusion of TAK-003 in Thailand's national immunization program.

Study 2: Determinants of Dengue Vaccine Acceptance among Thai Adults and Parents

This study aims to examine dengue vaccine acceptance and factors influencing vaccination decisions among Thai adults and parents of children aged 4-18 years. Understanding vaccine acceptance is essential for successful implementation of future dengue vaccination programs in Thailand.

This study will employ a sequential explanatory mixed-methods design consisting of two phases. The first phase is a cross-sectional survey conducted among Thai adults and parents attending outpatient clinics at two tertiary hospitals. Participants will complete a structured questionnaire assessing sociodemographic characteristics, dengue-related experiences, psychological antecedents of vaccination using a modified Thai version of the 7Cs model, willingness to pay, and dengue vaccine acceptance.

In the second phase, purposively selected participants from the quantitative survey will participate in semi-structured in-depth interviews to explore perceptions, beliefs, attitudes, and contextual factors influencing dengue vaccine decision-making. Quantitative and qualitative findings will be integrated to provide a comprehensive understanding of vaccine acceptance and hesitancy.

The findings will provide evidence to inform communication strategies, public health interventions, and policy development aimed at improving dengue vaccine uptake in Thailand.