Potential Public Health Impact of Updated COVID-19 Vaccination Strategies in Thailand: Epidemiological Data Update

This study evaluates the anticipated health and economic effects of multiple COVID-19 vaccination strategies using an updated vaccine in Thailand.

A previously published hybrid decision tree and Markov model, originally developed for the USA, was calibrated using Thailand-specific epidemiological, demographic, and economic data from 2024. The model assessed several age- and risk-based vaccination strategies assuming vaccine uptake ranging from 20% to 50%. Health outcomes (cases, hospitalizations, deaths, and long COVID cases) and economic outcomes (long COVID costs, direct medical costs, and productivity losses) were projected from payer and societal perspectives. Vaccine effectiveness was assumed to be 50% against infection, 60% against symptoms, and 70% against severe disease, with a 6-month duration of protection.

Vaccinating individuals aged 60 years and above and high-risk individuals aged 6 months to 59 years was projected to prevent 318,700 infections, 9147 hospitalizations, and 1061 deaths in 1 year. This strategy was estimated to yield THB 3300 million in direct medical cost savings and THB 2695 million in productivity loss savings. Increasing coverage in this population to 50% could amplify these reductions by up to 150%.

With updated Thai data, analyses suggest that use of an adapted COVID-19 vaccine could continue to generate considerable public-health and economic gains, particularly when coverage among older adults and high-risk groups is expanded. These findings carry implications for sustaining preparedness and guiding national vaccination policy.