Whooping cough surged in Japan in 2025 as it ebbed elsewhere in the Pacific
National surveillance recorded 60,826 cases in Japan by July 2025 — about 15 times the previous year's 4054 — concentrated in school-age children, while four other countries had already peaked and declined.
| Group | Value (value) |
|---|---|
| 2025 (to 31 July) | 60826 |
| Previous year | 4054 |
Whooping cough has come back worldwide since the COVID-19 pandemic, but it has not come back evenly. A retrospective study in Scientific Reports analysed national surveillance data from four Western Pacific countries — Japan, Australia, New Zealand and China — and the United States, and found that the timing and scale of the resurgence diverged sharply, with a late and unusually large outbreak in Japan standing apart from the pattern elsewhere [s1].
Pertussis, caused by the bacterium Bordetella pertussis, is one of the most contagious respiratory diseases and is most dangerous to infants, who are too young to be fully vaccinated [s1]. Cases collapsed in 2020–2022 when pandemic measures suppressed respiratory transmission, and public-health researchers have been watching for the rebound ever since.
What the surveillance shows
All five countries recorded a significant increase in cases between the period of pandemic preventive measures (2020–2022) and the subsequent loosening of those measures (2023–2025), a difference the authors report at p<0.001 [s1]. But most of the study countries saw their peaks arrive in 2024 and then decline. Japan was the exception [s1].
A significant outbreak began relatively late in Japan in 2025. As of 31 July 2025 — a seven-month, partial count the authors caution may be an underestimate — the country had recorded 60,826 cases, an incidence rate of 49.13 per 100,000 population [s1]. That is about 15 times the 4054 cases reported in the whole of the previous year [s1]. The surge was concentrated not in infants but in older children: individuals aged 5 to 19 years, and adolescents in particular, made up 56.6% of cases, and the outbreak was concentrated in non-metropolitan prefectures rather than the big cities [s1].
Why the age pattern matters
That a resurgence falls heaviest on school-age children and adolescents is a clue about immunity, not just exposure. The authors link Japan's 2025 surge to a lack of routine booster vaccinations, which would leave protection to wane as children move through primary and secondary school [s1]. It is a pattern consistent with a broader concern in the field: the protection conferred by modern acellular pertussis vaccines, while safe and effective in the short term, wanes faster than that of the older whole-cell vaccines they largely replaced.
A narrative review published in Vaccines sets out why the two vaccine types are not interchangeable. Whole-cell and acellular pertussis vaccines differ in their underlying immunology, the durability of the protection they give, their reactogenicity and their programmatic use, and the review notes that pertussis has resurged worldwide despite long-standing vaccination programmes [s2]. Those differences in durability are central to current debates about how often, and with what product, booster doses should be given [s2].
The programmatic choices behind those debates are not uniform even within Europe. The review observes that Poland is the only country in the European Union or European Economic Area that routinely primes infants with the whole-cell vaccine while reserving acellular products for boosters, pregnancy and selected indications — an arrangement it describes as an informative natural comparison between the two platforms [s2]. The review, which drew on literature and documents from the World Health Organization, the European Centre for Disease Prevention and Control, national public-health institutes and regulators through July 2026, did not attempt a quantitative synthesis, so it maps the trade-offs rather than ranking the vaccines [s2]. That framing fits Japan's data: a surge falling on older children and adolescents, in non-metropolitan prefectures, is the signature of waning protection in cohorts primed years earlier, not of a vaccine that never worked [s1].
What it means
The headline number — more than 60,000 cases in seven months in a high-income country with an established immunisation programme — is a reminder that a vaccine-preventable disease can rebound quickly when population immunity thins and transmission returns to normal [s1]. But the study is surveillance data, not a controlled experiment, and it carries the usual limits: case counts depend on testing and reporting practices that differ between countries, the 2025 Japanese figure is a partial-year total, and the link to missed boosters is an inference the authors draw from the age distribution rather than a measured cause [s1].
The practical reading is narrower than "the vaccine is failing." Pertussis vaccines remain the central tool against the disease; the question the data raise is about schedule and timing — whether booster doses in adolescence, and vaccination in pregnancy to protect newborns, are reaching enough people to blunt the kind of surge Japan saw [s1][s2]. What to watch next is whether Japan's outbreak follows the others into decline through 2026, and whether countries with ageing acellular-vaccine cohorts see similar school-age resurgences. Readers in affected areas should treat the figures as a signal to check their own and their children's immunisation status against local guidance, not as a verdict on any single vaccine.
Sources
- [s1] Pertussis resurgence after the COVID-19 pandemic in four Western Pacific Countries and the USA, highlighting the 2025 outbreak in Japan. Scientific Reports, 2026. https://doi.org/10.1038/s41598-026-47780-4
- [s2] Whole-Cell and Acellular Pertussis Vaccines: A Narrative Review of Biological, Clinical, Safety, Epidemiological, and Supply Aspects. Vaccines, 2026. https://doi.org/10.3390/vaccines14090775
Sources
- Pertussis resurgence after the COVID-19 pandemic in four Western Pacific Countries and the USA, highlighting the 2025 outbreak in Japan — Scientific Reports , April 18, 2026
- Whole-Cell and Acellular Pertussis Vaccines: A Narrative Review of Biological, Clinical, Safety, Epidemiological, and Supply Aspects — Vaccines , September 3, 2026
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