Predictive model of public health impact of herpes zoster vaccination and related costs for adults aged ≥50 years in Republic of Korea

Given the rapidly aging population in South Korea, the growing incidence and burden of herpes zoster (HZ) increase the need for HZ prevention. However, the public health impact of HZ vaccination has not been assessed in South Korea. This predictive modeling study estimated the public health and economic impact of available HZ vaccination strategies, using the ZOster ecoNomic Analysis (ZONA) model adapted with South Korea-specific inputs. Base case analysis involved adults ≥50 y of age (YOA), exploring three vaccination strategies (no vaccination/recombinant zoster vaccine [RZV]/zoster vaccine live [ZVL]) under mass vaccination (70% coverage) settings. Scenario and sensitivity analyses were performed. In the base case population of 23,329,743 people, without vaccination, 6,978,500 HZ and 733,278 postherpetic neuralgia (PHN) cases were estimated over their remaining lifetime. Compared with no vaccination, RZV vaccination avoided 3,675,898 HZ and 372,714 PHN cases, while ZVL vaccination avoided 1,013,654 HZ and 107,590 PHN cases. RZV and ZVL avoided 430,190 and 81,975 hospitalizations, respectively. Without considering the costs of vaccination, HZ-related medical costs averted with RZV were 1,399 billion KRW (1,026 million USD), and productivity loss averted was 503 billion KRW (368 million USD); ZVL averted 419 billion KRW (307 million USD) in HZ-related medical costs and 241 billion KRW (177 million USD) in productivity loss. Results were robust under scenario and sensitivity analyses. Mass RZV vaccination among adults ≥50 YOA in South Korea would considerably reduce HZ-related burden. Results may support value assessment and decision-making regarding vaccination strategies for HZ prevention in South Korea. In South Korea, the number of people with shingles is rising due to the aging population, with worrying health and economic impacts. There are currently two types of shingles vaccines available in South Korea: the recombinant zoster vaccine (RZV) and zoster vaccine live (ZVL). This study used mathematical modeling to find out how different vaccination strategies (no vaccine, RZV or ZVL) can reduce cases of shingles and its complications, avoid healthcare resource usage, as well as reduce the economic impact when fewer people are infected. For a population of around 23 million Korean adults aged 50 y and above, the burden of shingles was high without vaccination − 6,978,500 cases of shingles and 733,278 cases of shingles-related long-term nerve pain were estimated. ZVL vaccination was estimated to avoid 1,013,654 cases of shingles, 107,590 cases of nerve pain and 81,975 hospitalizations. RZV vaccination was estimated to avoid even more cases of shingles (3,675,898 cases), nerve pain (372,714 cases) and hospitalizations (430,190). As a result of fewer shingles cases, the economic impact was also reduced because medical costs and resource use were lower, and fewer people needed to take time off work (productivity loss) for treatment. Compared with no vaccination, ZVL was estimated to save 660 billion KRW (484 million USD) and RZV was estimated to save 1,902 billion KRW (1,394 million USD) in HZ-related medical costs and productivity loss without considering the costs of vaccination. Overall, these results may help local health experts and policymakers make decisions about shingles prevention.