Assessing the cost-effectiveness of COVID-19 vaccines in a low incidence and low mortality setting: the case of Thailand at start of the pandemic

Abstract

Objective This study aimed to assess the cost-effectiveness of COVID-19 vaccines, preferred COVID-19 vaccine profiles, and the preferred vaccination strategies in Thailand. Methods An age-structured transmission dynamic model was developed based on key local data to evaluate economic consequences, including cost and health outcome in terms of life-years (LYs) saved. We considered COVID-19 vaccines with different profiles and different vaccination strategies such as vaccinating elderly age groups (over 65s) or high-incidence groups, i.e. adults between 20 and 39 years old who have contributed to more than 60% of total COVID-19 cases in the country thus far. Analyses employed a societal perspective in a 1-year time horizon using a cost-effectiveness threshold of 160,000 THB per LY saved. Deterministic and probabilistic sensitivity analyses were performed to identify and characterize uncertainty in the model. Results COVID-19 vaccines that block infection combined with social distancing were cost-saving regardless of the target population compared to social distancing alone (with no vaccination). For vaccines that block infection, the preferred (cost-effective) strategy was to vaccinate the high incidence group. Meanwhile, COVID-19 vaccines that reduces severity (including hospitalization and mortality) were cost-effective when the elderly were vaccinated, while vaccinating the high-incidence group was not cost-effective with this vaccine type. Regardless of vaccine type, higher vaccination coverage, higher efficacy, and longer protection duration were always preferred. More so, vaccination with social distancing measures was always preferred to strategies without social distancing. Quarantine-related costs were a major cost component affecting the cost-effectiveness of COVID-19 vaccines. Conclusion COVID-19 vaccines are good value for money even in a relatively low-incidence and low-mortality setting such as Thailand, if the appropriate groups are vaccinated. The preferred vaccination strategies depend on the type of vaccine efficacy. Social distancing measures should accompany a vaccination strategy.

Economic evaluation of COVID-19 vaccination: A systematic review

“…Only one study did not report the perspective adopted [ 39 ] ( Table 2 ). At least four studies specified a vaccination coverage of less than 50% [ 21 , 27 , 30 , 40 ], eight had a vaccination coverage of 50%-75% [ 22 , 26 , 34 - 37 , 44 , 45 ], and one specified a vaccination coverage of 100% [ 41 ]. Moreover, three studies presented a range of two to three categories of vaccination coverage each [ 25 , 32 , 42 ].…”

“…The remaining included studies used more than one sensitivity analysis, i.e. PSA and one-way sensitivity analysis [ 21 , 36 , 44 , 45 ].…”

“…Each analysis used a different evaluation to determine whether the use of vaccinations was considered cost-effective, e.g. by considering the procurement of the vaccine program compared with the absence of a vaccination program [ 21 , 26 , 33 , 36 , 39 , 41 , 45 , 48 , 50 ], the coverage of the vaccine used [ 37 , 40 , 42 , 49 ], the existence of priority vaccines for specific populations [ 25 , 30 , 33 , 34 , 38 , 41 ], the efficacy of many vaccines on the market [ 23 , 24 , 29 , 35 , 41 , 43 ], and the provision of boosters following vaccination [ 34 ].…”

“…Several studies did not conduct sensitivity analysis to determine the uncertainty of the analysis [ 24 , 28 , 39 , 41 , 43 ], but most did. Reproduction number [ 21 , 25 , 49 ], vaccine price/cost [ 22 , 23 , 33 , 41 , 48 ], vaccination program [ 26 , 42 , 45 ], vaccine efficacy [ 29 , 30 , 33 , 36 , 40 , 41 , 48 - 50 ], population/infection incidence [ 33 , 34 , 38 ], hospitalisation fee [ 35 ], and discount rate and mortality [ 37 ] were the most reported sensitive parameters in the sensitivity analysis. Vaccine cost was one of the most essential factors in determining cost-effectiveness.…”

“…Table 1 provides the characteristics of the 25 included studies, 23 of which were single-country studies, 11 were from LMICs [21][22][23][24][25]29,35,[38][39][40]43,44], and 12 were studies from high-income countries (HICs) [26][27][28][30][31][32][33][34][35]37,41,45]. The two remaining studies were conducted in multiple countries; the first one comprised four analyses from LMICs and two analyses from HICs [36], while the other study comprised 12 analyses in LMICs [42].…”