Measles cases in Japan reach 299 by April 12, exceeding 2025 total
Measles cases in Japan reached 299 as of April 12, 2026, surpassing last year’s total, prompting health authorities to push vaccinations and caution the public. The Japan Institute for Health Security reported the figures on April 22, noting a weekly peak of 56 new infections in the week through April 12. Tokyo accounted for the largest share of cases, with several prefectures also reporting clusters. Officials urged those with symptoms to seek medical advice by phone and to avoid using public transport.
Measles cases surpass 2025 total by mid-April
The institute’s preliminary tally of 299 cases through April 12 exceeded the 265 cases recorded for the entirety of 2025. The week ending April 12 produced a record single-week count of 56 cases, indicating an acceleration of confirmed infections in early April. Public health officials described the rise as concerning and said they would continue monitoring case counts and transmission patterns nationwide.
Late reporting or delays in confirmation could still change the final seasonal totals, the institute added. However, the current trend has already prompted renewed outreach on vaccination and testing from multiple agencies. Authorities emphasized the need for vigilance, particularly in areas with rising counts.
Tokyo and prefectural hotspots recorded
Tokyo recorded 108 cases as of April 12, making it the epicenter of the current surge. Kanagawa reported 31 cases, Kagoshima 28, and both Chiba and Aichi reported 23 cases each, according to the institute’s breakdown. Health officials pointed to the combination of high population density in metropolitan areas and pockets of under-vaccinated communities as factors that can accelerate spread.
Local health bureaus in the affected prefectures have increased surveillance and are coordinating with medical facilities to speed diagnosis and isolate cases where possible. Schools, daycare centers and other congregate settings in some districts have been advised to review infection-control measures and to inform parents about the signs of measles.
Majority of cases show vaccination gaps
Health officials reported that approximately 74 percent of those infected this year had either received only one dose of measles vaccine, had no recorded vaccination, or had an unknown vaccination history. The finding has refocused attention on Japan’s two-dose schedule, which is offered at public expense at around age one and again before school entry. Public-health experts say that full two-dose coverage is critical to preventing outbreaks and protecting infants and immunocompromised people who cannot be vaccinated.
Authorities are urging people to check their own or their children’s vaccination records and to complete missing doses when indicated. Employers and schools have been asked to facilitate access to vaccination information and encourage compliance with recommended schedules.
Testing, record checks and medical guidance
Certain medical institutions can assess vaccination history and perform tests for post-infection immunity at personal expense, officials said. These services can confirm whether individuals have protective antibodies or need a vaccine dose to boost immunity. Health centers and clinics are prepared to provide testing and counseling, particularly for those working with young children or vulnerable populations.
The Health, Labor and Welfare Ministry has advised anyone who develops symptoms consistent with measles—such as high fever, cough, runny nose, red eyes and a characteristic rash—to call ahead to a medical facility rather than arriving in person. Patients are specifically asked to avoid using public transportation when seeking care, to reduce the risk of exposing others during travel.
Authorities call for targeted vaccination push
In response to the surge, public-health authorities are mobilizing targeted vaccination drives, especially in high-incidence wards and prefectures. Local governments are being asked to publicize free or subsidized vaccination opportunities and to offer flexible clinic hours to reach working adults and parents. Health officials are also coordinating with schools and childcare providers to confirm vaccination records and to offer catch-up immunizations where necessary.
Public messaging will focus on the safety and efficacy of the measles vaccine and on the potential severity of measles complications, including pneumonia and, in rare cases, encephalitis. Officials stressed that increasing two-dose coverage remains the most reliable way to halt chains of transmission and protect those unable to receive the vaccine.
The sudden rise in cases has renewed discussion about routine immunization coverage and the need for ongoing surveillance. Health agencies say they will publish updated figures as more data are confirmed and will continue to advise the public on prevention and care.
