Cost-effectiveness and budget impact analyses of introducing typhoid conjugate vaccine into Indonesia's national immunisation program.
BACKGROUND Typhoid fever remains a health threat in endemic countries. In Indonesia, it causes an estimated 470,000 cases and 6000 deaths annually. We assessed the cost-effectiveness and budget impact of introducing the typhoid conjugate vaccine (TCV) into Indonesia's routine National Immunisation Program (NIP) at 9 months of age, with or without a catch-up campaign up to 15 years of age. METHODS A validated dynamic model of typhoid transmission was used to project health outcomes over a 30-year analytical horison for each scenario. Cost-of-illness data were drawn from the Surveillance of Typhoid Fever in Indonesia study and published literature. Incremental cost-effectiveness ratios (ICERs) were estimated from healthcare sector and societal perspectives. Uncertainty was explored using one-way sensitivity analysis (OWSA) and probabilistic sensitivity analysis (PSA). Budget impact analysis supported annual fiscal planning. RESULTS Six-year budget impact costs were US$61 million (routine) and US$251 million (routine and catch-up), equivalent to 0.48%-2.95% and 2.97%-9.84% of the annual national immunisation budget, respectively. Compared to no vaccination, routine TCV yielded ICERs at US$240.6 and US$238.8 per DALY averted from the healthcare sector and societal perspectives, respectively, corresponding to 5% of GDP per capita. Compared with routine immunisation alone, adding a catch-up campaign yielded ICERs of US$521.3 and US$519.5 per DALY averted from the healthcare sector and societal perspective, respectively, corresponding to approximately 11% of GDP per capita. OWSA showed that both strategies remained very cost-effective at a willingness-to-pay threshold of 1xGDP. PSA estimated probabilities of cost-effectiveness of 99.7% (routine and catch-up vs. routine) and 99.2% (routine vs. no vaccination). The multi-strategy cost-effectiveness acceptability curve identified the combined routine and catch-up campaign as the optimal strategy. CONCLUSION Introducing TCV into Indonesia's NIP is projected to be very cost-effective. A routine-only program requires a lower budget, but adding a catch-up campaign is an optimal strategy with greater public health impact while remaining very cost-effective. FUNDING Gates Foundation grants to Murdoch Children's Research Institute in collaboration with Universitas Gadjah Mada [ref. no. INV-003867] and to TyVAC 2.0 [ref. no. INV-030857].