The scale of the findings is striking. At their peak, annual prevalence estimates reached 347 cases per 100,000 population in primary care settings in 2017 and 314 per 100,000 in hospitals in 2016, figures that consistently exceed the threshold of more than 100 cases per 100,000 person-years used to define high-burden settings. Even after years of gradual decline, the most recent estimates from 2023 stood at 143 per 100,000 in primary care and 167 per 100,000 in hospitals, still well above that benchmark. Hospital admissions accounted for 47.62 percent of all typhoid-related visits, and cumulative deaths over the nine-year period included 11,991 recorded in hospitals, corresponding to an average annual hospital mortality rate of 0.57 per 100,000 population.

Methodologically, the study is a serial cross-sectional analysis built on an unweighted sample of 2,499,681 unique individual records, which, after applying BPJS Kesehatan’s stratified sampling weights, represents a national population of approximately 290 million people. Cases were identified using physician-assigned ICD-10 codes, primarily A01.0 for typhoid fever, recorded as either primary or secondary diagnoses. To avoid inflating prevalence with repeat consultations for the same illness, the researchers applied an episode-based filtering approach: encounters occurring within 30 days of a preceding record for the same individual were treated as part of a single clinical episode, a boundary chosen because typhoid’s incubation period typically ranges from 6 to 30 days and relapses most commonly occur two to three weeks after treatment ends. Only the final record within each episode was retained for analysis.

The choice of data source matters because diagnosing typhoid fever in endemic settings is notoriously difficult. The Widal agglutination test, long used in low-resource settings, has poor sensitivity and specificity because of high background seroprevalence, and rapid diagnostic tests offer only modest improvements. Blood culture remains the reference standard, but its sensitivity drops after prior antibiotic use, and laboratory capacity and cost constraints mean microbiological confirmation is rarely performed in routine Indonesian practice. In primary care, where reimbursement is capitation-based, laboratory confirmation is not routinely required at all; in hospitals, supporting investigations such as Tubex, Typhidot, or Widal testing are generally undertaken for reimbursement claims, though these do not replace culture confirmation. The study’s estimates therefore describe the burden of physician-coded typhoid requiring healthcare utilisation rather than microbiologically confirmed disease, a distinction the authors acknowledge carefully.

Demographically, the burden fell unevenly. Adults aged 19 to 64 accounted for roughly half of all typhoid-related visits, yet the highest prevalence was observed among children under five years of age in both primary care and hospital settings. Adjusted analyses using Poisson regression with robust variance estimation revealed that children aged 0 to 5 years had a modestly higher likelihood of hospitalisation compared with working-age adults, with an adjusted prevalence ratio of 1.02, while adolescents aged 6 to 18 showed a ratio of 1.03. The most pronounced elevation appeared among people aged 65 and older, whose adjusted prevalence ratio of 1.07 was the highest of any age group, despite this group having the lowest overall prevalence of typhoid-related visits. The authors suggest this may reflect comorbidities, frailty, and a lower clinical threshold for admitting older patients rather than greater disease severity per se.

Socioeconomic vulnerability emerged as another powerful determinant. Individuals enrolled in the subsidised insurance scheme, which serves low-income households, had a 7 percent higher likelihood of hospitalisation than those in the formal sector, with an adjusted prevalence ratio of 1.07. Members of Class III, the most affordable tier of care with the simplest inpatient facilities, contributed the largest share of visits across all settings. These patterns, the researchers argue, reflect underlying socioeconomic disadvantage and potential barriers to timely access to care, meaning that by the time subsidised patients reach hospital, their illness may be more advanced. The intersection of age-related vulnerability and social disadvantage, they conclude, shapes severe disease trajectories in ways that targeted interventions must address.

Geographically, the study uncovered pronounced subnational clustering that national-level statistics had long obscured. Primary care prevalence was highest in Central Java province at a mean annual 302 per 100,000, followed by Bengkulu at 289, while hospital prevalence peaked in Aceh at 496 per 100,000, followed by Gorontalo and North Sumatra. When provinces were aggregated into the INA-CBGs regional classification, the highest annual prevalence reached 2,367 visits per 100,000 population in region 1, covering Java, Indonesia’s most populous island, for primary care, and 2,213 per 100,000 in region 3, covering Sulawesi and parts of Sumatra and Kalimantan, for hospitals. Urban areas consistently showed higher prevalence than rural ones across both care settings throughout the study period.

The concentration of cases in densely populated Java is particularly revealing because it runs counter to a simple sanitation narrative. Several provinces in Java exhibited both relatively high percentages of households with access to improved sanitation and high typhoid prevalence, while provinces outside Java with better sanitation access generally showed lower prevalence. Previous research has documented widespread use of shallow, contaminated groundwater as a household drinking water source and poor sanitation management in dense and informal urban settlements on Java, and parts of Sumatra and Sulawesi where cases clustered also show WASH infrastructure access below the national figure. The eastern provinces of Papua and Papua Barat recorded the lowest prevalence, at 24 and 10 per 100,000 respectively in primary care, but the authors caution this likely reflects lower healthcare utilisation and under-ascertainment rather than genuinely low transmission.

The temporal trends carry their own lessons. A marked decline in cases occurred during 2020 and 2021, coinciding with the COVID-19 pandemic, likely reflecting the reallocation of 20 to 40 percent of general ward beds to COVID-19 care, reduced healthcare-seeking, and non-pharmaceutical interventions such as social distancing and improved hand hygiene that may have limited faecal-oral transmission. When cases rebounded in 2022, the increase was more pronounced among inpatients than outpatients, which the authors attribute to the restoration of routine inpatient services rather than a true rise in disease severity. Earlier fluctuations during 2016 and 2017 may relate to the rapid expansion of insurance membership, evolving referral policies, and maturation of coding practices during the early phase of the scheme’s implementation.

The implications extend well beyond Indonesian borders. The Global Burden of Disease 2023 study estimates that Indonesia has the highest typhoid incidence, 99 per 100,000, and mortality rate, 1.29 per 100,000, in Southeast Asia, yet those figures rely substantially on modelled extrapolation in a country lacking nationwide culture-confirmed surveillance. The new claims-based estimates, which exceed even the GBD figures, arrive as neighbouring countries move forward with typhoid conjugate vaccine introduction: Nepal and Pakistan have incorporated the vaccine into routine immunisation, and Bangladesh introduced it in 2025, following the World Health Organization’s 2018 recommendation of a single dose for children from six months of age. Indonesia, however, continues to face financing constraints and competing priorities, with policymakers citing a lack of robust contemporary epidemiological data. The authors also point to complementary environmental surveillance showing Salmonella Typhi in 13 percent of 406 wastewater samples collected from treatment plants, manholes, rivers, and public spaces, evidence of persistent community transmission. Combined with rising multidrug and extensively drug-resistant strains documented across endemic settings, and imported cases linked to travel from Indonesia reported abroad, the converging evidence strengthens the case for introducing the vaccine alongside targeted water and sanitation improvements, prioritising high-burden regions and vulnerable populations, and building serosurveillance and wastewater monitoring into the country’s surveillance architecture.

Subject of Research: Population-based epidemiology of typhoid fever in Indonesia using national health insurance claims data

Article Title: Burden of typhoid fever in primary and hospital care in Indonesia: a serial cross-sectional study using national health insurance (BPJS Kesehatan) data, 2015–2023

Article References: Oktaria, V., Ramadhani, A. D., Maula, A. W., Murni, I. K., Watts, E., Baehaqi, I. S., Dinari, R., Wiryawan, D. A., Daniel, D., Donato, C. M., & Bines, J. E. (2026). Burden of typhoid fever in primary and hospital care in Indonesia: a serial cross-sectional study using national health insurance (BPJS Kesehatan) data, 2015–2023. The Lancet Regional Health – Western Pacific, 75, Article 101994. https://doi.org/10.1016/j.lanwpc.2026.101994

Image Credits: AI Generated

DOI: 10.1016/j.lanwpc.2026.101994

Keywords: typhoid fever, Indonesia, Salmonella Typhi, BPJS Kesehatan, epidemiology, hospitalisation, typhoid conjugate vaccine, water sanitation and hygiene, antimicrobial resistance, health insurance claims, subnational disparities, wastewater surveillance