Tokyo, May 9 (IANS) Japan has recorded more than 400 measles cases since January, a national health research body said.

According to the Japan Institute for Health Security, medical institutions across the country reported 68 measles cases in the week through April 26, bringing the cumulative total for this year to 436. In comparison, 96 cases were recorded during the same period last year, and the full-year total for 2025 stood at 265.

Tokyo alone has recorded 211 cases this year, accounting for nearly half of the national total. Including the neighboring prefectures of Kanagawa, Chiba and Saitama, the greater Tokyo metropolitan area has reported more than 300 cases in total.

In a notice issued in late April, the institute said most domestic measles patients this year were teenagers and people in their 20s, around half of whom had either not completed the recommended two-dose vaccination schedule or had unclear vaccination histories.

The highest annual number of measles cases in Japan in the past decade was 744 in 2019.

The institute warned that measles is highly contagious, with more than 90 per cent of non-immune individuals likely to become infected after exposure to the virus. Severe cases can lead to complications such as pneumonia and encephalitis.

Japan was declared measles-free by the World Health Organization in 2015. However, since 2023, the number of measles cases reported worldwide has continued to rise, increasing the risk of imported infections.

The institute said receiving two doses of the vaccine remains the most effective way to prevent measles infection and severe illness. It also advised travelers heading to countries or regions where measles may be spreading to confirm their vaccination status beforehand, Xinhua news agency reported.

People experiencing symptoms such as fever, rash, coughing, or conjunctival redness were urged to contact medical institutions before seeking treatment and to inform healthcare providers of any recent overseas travel or contact with infected individuals.

–IANS

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