Recent data released by Japanese health authorities on February 24, 2026, indicates an upward trend in measles cases across the country. In the first seven weeks of this year, 43 new cases were confirmed, surpassing the figures from the same period last year. In response, the government has published the itineraries of infected individuals, urging anyone who may have crossed paths with them to seek immediate medical attention if they develop symptoms such as a fever or rash.

According to data from the Japan Institute for Health Security (JIHS), as of February 18, Japan has reported a total of 43 measles cases this year. Among them, 13 are imported cases, 22 were contracted domestically, and the infection sites for the remaining eight have yet to be determined. Geographically, Tokyo, Osaka, Chiba and Niigata prefectures have seen the highest number of confirmed cases. Demographically, more than half of the infected patients are between the ages of 20 and 40.

Local governments, including those in Tokyo and Osaka, have released the travel histories of the patients. Officials advise anyone who visited the same locations or shared public transportation to monitor their health for 21 days following potential exposure. If symptoms like fever or rash occur, individuals are instructed to notify medical facilities promptly, wear a mask when seeking treatment and avoid using public transit.

Japanese media reports highlight that measles is highly contagious; a single patient can infect 12 to 14 susceptible individuals. The incubation period typically ranges from 10 to 12 days but can last up to 21 days. Symptoms include fever, upper respiratory tract inflammation, coughing and conjunctivitis. In severe cases, the disease can lead to complications such as pneumonia.

Statistics show that measles cases in Japan remained low between 2020 and 2022, with fewer than 10 confirmed cases annually. However, the number rose to 28 in 2023, reached 45 in 2024, and surged significantly to 265 cases in 2025.