Hepatitis B Deaths Keep Rising in the Western Pacific Even as New Infections Fall, Decade-Long Analysis Finds

A decade of modelled data from 34 countries and areas across the World Health Organization’s Western Pacific Region reveals a troubling paradox at the heart of the global fight against hepatitis B: while new chronic infections have fallen steeply, deaths from the virus have continued to climb. The analysis, published in The Lancet Regional Health – Western Pacific, applied a common statistical framework to country-level estimates from the Center for Disease Analysis Foundation’s Polaris Observatory between 2015 and 2024, and found that in 19 of the 34 countries and areas studied — 55.9 percent — chronic hepatitis B virus incidence was declining at the same time as HBV-related mortality was rising. Only Japan and New Zealand achieved declines in both measures over the decade.

The scale of the region’s burden makes these findings consequential far beyond the Western Pacific. According to the WHO’s 2026 Global Hepatitis Report, roughly 240 million people were living with chronic HBV infection worldwide in 2024, and the virus caused about 1.1 million deaths from cirrhosis and liver cancer — a 17 percent increase in HBV-related mortality since 2015. The Western Pacific alone accounted for an estimated 102 million people living with hepatitis B in 2024, and several countries that contribute disproportionately to the global toll, including China, the Philippines, Viet Nam and Indonesia, sit within the region. WHO’s elimination strategy calls for a 90 percent reduction in new infections and a 65 percent reduction in hepatitis-related deaths by 2030, compared with 2015 baselines.

Between 2015 and 2024, the modelled estimates show genuine progress on the transmission side of the ledger. Total HBV prevalence in the region fell from 5.28 percent to 4.58 percent, corresponding to a drop from about 100.8 million to 89.7 million people living with the virus. Chronic HBV incidence fell from 6.32 to 3.16 new infections per 100,000 population, and prevalence among children under five declined from 0.40 percent to 0.28 percent — although that childhood figure has plateaued since 2019, well above the WHO 2030 target of 0.1 percent. Mortality moved in the opposite direction: the HBV-related death rate rose from 22.88 to 24.70 per 100,000, with estimated annual deaths climbing from 436,363 to 484,055.

The researchers quantified country-specific trends using estimated annual percentage changes, derived from log-linear regression of modelled annual rates against calendar year. Chronic incidence was classified as declining in 22 of the 34 countries and areas, with the steepest falls in Japan (an EAPC of −19.24 percent per year) and the Republic of Korea (−15.66 percent). Mortality, by contrast, was classified as increasing in 31 of 34 countries and areas, spanning every analytical subregion the team examined: East Asia, Southeast Asia, Australasia and the Pacific Island Countries and Territories. Japan (−3.09 percent per year) and New Zealand (−1.37 percent) were the only exceptions. The Marshall Islands recorded the sharpest mortality increase at 6.44 percent per year, followed by Tonga and Cambodia at 3.97 percent each.

Underlying the regional averages is striking heterogeneity. Among children under five, prevalence in 2024 had fallen to 0.08 percent in China, 0.03 percent in the Republic of Korea, 0.01 percent in Japan, 0.06 percent in Australia and 0.02 percent in New Zealand — all meeting the 2030 elimination target of 0.1 percent or lower. Yet in Papua New Guinea, under-five prevalence rose 24.61 percent over the decade to reach 2.38 percent, and increases were also recorded in New Caledonia, Samoa and Vanuatu. Ten other Pacific countries and territories still had childhood prevalence above 1 percent in 2024. Total prevalence rose only in the Marshall Islands (+22.73 percent) and Tuvalu (+1.49 percent), but the range across the region was enormous, from 0.73 percent in Japan to 9.16 percent in Tonga.

The statistical relationship between incidence and mortality trends was, notably, only modest. Country-level estimated annual percentage changes for chronic incidence and mortality were positively correlated (Pearson r = 0.39), and incidence trends explained just 15.2 percent of the between-country variation in mortality trends. That weak coupling reinforces the study’s central methodological message: the two indicators measure temporally distinct dimensions of elimination. Chronic HBV infection progresses over decades to decompensated cirrhosis and hepatocellular carcinoma — which accounts for roughly 80 percent of primary liver cancers globally — so today’s deaths largely reflect infections acquired long before recent vaccination gains. The authors caution that their ecological design cannot determine whether rising mortality reflects population ageing, the accumulated legacy of longstanding infection, gaps in diagnosis and treatment, or changes in how deaths are recorded.

Vaccination coverage, the backbone of HBV prevention, remained comparatively high regionally but varied dramatically between countries. Three-dose infant vaccination coverage stayed above 90 percent across most of the study period, but birth-dose coverage — the most critical intervention for preventing mother-to-child transmission — hovered around 80 percent, short of the 2030 target of 90 percent or more. In 2024, birth-dose coverage ranged from 99.65 percent in Tuvalu down to 26.20 percent in Papua New Guinea, where three-dose coverage had also fallen to 39.84 percent. Fiji’s birth-dose coverage collapsed from 99 percent in 2020 to 39.12 percent in 2024, and declines in three-dose coverage were seen in the Cook Islands and Samoa. Japan and New Zealand, which run targeted rather than universal birth-dose programmes, register low nominal birth-dose coverage for that reason rather than programme failure.

Exploratory analyses found no robust statistical association between national vaccination coverage levels, or changes in coverage, and changes in childhood infection or chronic incidence after adjustment for multiple comparisons — a result the authors stress does not challenge established vaccine effectiveness, but instead highlights the limits of contemporary coverage figures as proxies for cumulative prevention performance. Progress towards WHO milestones was similarly uneven: by 2024, only Australia (3.70 deaths per 100,000) had reached the 2030 mortality target of 4 per 100,000, with Japan and French Polynesia the only others below the 2025 interim threshold of 7 per 100,000. Neither the study’s subregional grouping nor an alternative World Bank income classification explained much of the observed heterogeneity, pointing instead to country-specific programme gaps such as those documented in Papua New Guinea, where out-of-facility births, cold-chain constraints and vaccine availability impede timely birth-dose delivery.

The implications are stark for elimination strategy. In China, despite dramatic reductions in childhood infection, an estimated 75 million people remain chronically infected with substantial diagnosis and treatment gaps, and infection is increasingly concentrated in older cohorts. As vaccination programmes mature, the authors argue, near-term reductions in cirrhosis and liver cancer will depend less on preventing new infections and more on clinical management of people already living with the virus — expanding testing, linking patients to care, widening access to antiviral therapy, and surveillance for liver cancer, in line with WHO’s 2024 treatment guidelines. Elimination monitoring, they conclude, should treat transmission, care-cascade performance and mortality as complementary but distinct outcomes, supported by better age-specific mortality data and simplified diagnostics such as point-of-care HBV DNA testing in settings with limited laboratory capacity.

The study also carries important caveats for interpretation. Its estimates derive from a single dynamic modelling framework rather than independent surveillance, uncertainty intervals were unavailable for incidence, mortality and liver-outcome measures, and some Pacific island settings share identical model-derived trajectories because regional comparators were used where local data were sparse. Residual autocorrelation was evident in many mortality models, meaning conventional confidence intervals may appear more precise than the underlying data warrant. The authors did include sensitivity analyses addressing influential observations, shared trajectories, departures from log-linearity and alternative country classifications, and the core finding — diverging incidence and mortality trajectories — held throughout. Even with those caveats, the message for the region that bears nearly half the world’s hepatitis B burden is difficult to escape: falling infection counts alone will not deliver elimination by 2030 without a parallel, and urgently scaled, assault on the disease burden carried by tens of millions already infected.

Subject of Research: Trends and disparities in hepatitis B virus burden and progress toward WHO elimination targets across the Western Pacific Region from 2015 to 2024.

Article Title: Trends and disparities in hepatitis B burden in the Western Pacific Region, 2015–2024: a subregional analysis using modelled data

Article References: Maung, H. T., Ghrabi, M. A., Morishita, F., Hubraj Yadav, R. P., Giang Tran, H. T., & Izumi, K. (2026). Trends and disparities in hepatitis B burden in the Western Pacific Region, 2015–2024: a subregional analysis using modelled data. The Lancet Regional Health – Western Pacific, 75, Article 101991. https://doi.org/10.1016/j.lanwpc.2026.101991

Image Credits: AI Generated

DOI: Not provided

Keywords: hepatitis B, Western Pacific Region, viral hepatitis, HBV mortality, vaccination, birth dose, epidemiology, elimination targets, cirrhosis, hepatocellular carcinoma, Polaris Observatory, public health