OBJECTIVES: Pneumococcal disease (PD) burden is evident amongst at-risk and high-risk elderly in Thailand. Although vaccination is the only public health strategy proven to reduce incidence of PD, pneumococcal vaccination is not part of Thai National Immunization Program (NIP). This study aims to evaluate the cost-effectiveness of pneumococcal vaccination for prevention of PD among at-risk and high-risk Thai elderly.

METHODS: A validated Markov model was used to estimate the cost-effectiveness over a lifetime horizon of three vaccination strategies: 23-valent pneumococcal polysaccharide vaccine (PPSV23), 13-valent pneumococcal conjugate vaccine (PCV13) and PCV13+PPSV23 comparing to no vaccination. The target populations were the elderly aged 65 years and over, who are at-risk (chronic respiratory disease, chronic heart disease, chronic liver disease, and diabetes) or high-risk (human immunodeficiency virus infection, organ transplantation, and chronic kidney disease). Cost, quality-adjusted life-years (QALY), and incremental cost-effectiveness ratios (ICERs) were estimated. The societal perspective was used, with costs and outcomes being discounted by 3%.

RESULTS: Compared to no vaccination, ICERs of all vaccination strategies did not fall under the current suggested willingness to pay (WTP) threshold from Thai guideline of 160,000 Thai Baht (THB), which is 1.6 times lower than Thai gross domestic product per capita. Among all strategies, PPSV23 provided the lowest ICERs in all sub-group populations, ranging from 337,343 to 1,558,621 THB/QALY in the chronic liver disease and diabetes subgroups, respectively. However, when using the WTP threshold recommended by World Health Organization (761,366 THB), all vaccination strategies were considered cost-effective in chronic liver disease patients. The PPSV23 and PCV13 strategies were also cost-effective in the high-risk population, with PPSV23 still being the most cost-effective strategy (ICERs: 517,489 and 669,171 THB/QALY for PPSV23 and PCV13, respectively).

CONCLUSIONS: To protect elderly who are at-risk or high-risk of PD, decision makers should consider inclusion of pneumococcal vaccination into Thai NIP.