The number of Japanese measles cases has soared, with a total of 511 confirmed cases reported this year.

The data released by Japan shows that the cumulative number of measles cases reported in the country so far this year has reached 511, which is nearly four times that of the same period last year.

According to a report by Xinhua News Agency, data released by the National Institute for Health Crisis Management of Japan on Tuesday (June 2) showed that from May 18 to 24, 2026, a total of 11 cases of measles were reported by medical institutions across Japan. So far this year, a total of 511 cases have been reported; among them, Tokyo Prefecture accounted for nearly half, with 253 cases. Over the past 10 years, the year with the highest number of measles cases in Japan was 2019, with 744 cases.

The National Institute for Health Crisis Management Research in Japan stated that measles is highly contagious. People without immunity who are exposed to the virus will develop the disease in over 90% of cases. Severe cases may experience symptoms such as pneumonia and encephalitis. The World Health Organization declared in 2015 that Japan had eradicated measles, meaning that there had been no detection of the local measles virus strain for at least three years. However, since 2023, the number of reported measles cases worldwide has continued to increase, and the risk of the virus being of overseas origin has been continuously rising. Getting two doses of the vaccine is the most effective method for preventing infection with measles and developing severe symptoms.