Estimating direct and indirect costs of hospitalised typhoid fever in Indonesia: A multisite healthcare facility and community survey

BACKGROUND: Typhoid fever, caused by the bacterium Salmonella enterica serovar Typhi (S. Typhi), remains a major global threat despite substantial declines over the past three decades. In 2021, an estimated 7.1 million (5.6 to 9.2 million) cases occurred worldwide. Following the WHO's recommendation, ten countries (excluding Indonesia) have introduced the typhoid conjugate vaccine (TCV). To inform decision-making for the potential introduction of TCV into Indonesia's National Immunisation Program, we estimated the direct and indirect costs of typhoid fever in Indonesia. METHODS: We conducted a multisite, incidence-based cost-of-illness study using a patient-level bottom-up costing approach in 23 hospitals and primary health centres (PHCs) across six provinces. Children (6 months to 17 years) and adults (≥18 years) hospitalised with ICD-10 A01 typhoid fever hospitalised with at least one positive typhoid serodiagnostic result during 2019-2023 (retrospective) and 2022-2023 (prospective), without other major infectious or chronic comorbidities, were identified from facility records. Direct medical costs were obtained retrospectively from hospital/PHC bills and clinical records, while direct non-medical and indirect (productivity loss) costs were collected prospectively through interviewer-administered household questionnaires. Sensitivity analyses re-estimated costs after excluding component-wise outliers and imputing missing income values using the provincial minimum wage. RESULTS: We collected 2,069 records (1,538 retrospective [891 children; 647 adults] and 531 prospective [329 children; 202 adults]) across six provinces. The weighted mean direct medical costs were US$177.0 ± 101.9 for children and US$199.8 ± 119.8 for adults, while the corresponding direct non-medical costs were US$43.7 ± 16.3 and US$39.0 ± 10.9, respectively. Indirect costs were US$23.9. ± 5.6 (children) and US$17.9 ± 5.5 (adults). Private hospitals had the highest total direct medical cost (US$254.4), while PHCs had the lowest (US$47.8). Costs varied substantially by provinces (BPJS tariff regions). CONCLUSION: Hospitalised typhoid fever imposes a substantial economic burden in Indonesia. These setting- and region-specific cost estimates can inform cost projections and cost-effectiveness analyses for the introduction of the typhoid conjugate vaccine in Indonesia.