Rise in Measles Cases: Prevent Further Spread without Underestimating Infections

Editorial

14:22 JST, April 2, 2026

The number of measles patients is on the rise. Measles is an infectious disease, with symptoms including high fever and a rash, and is known for being highly contagious. It is crucial for society as a whole to prevent the spread of infections.

As of March 22, the total number of measles cases nationwide this year has reached 152. This is the second fastest pace of increase in the past decade, following 2019.

By prefecture, Tokyo has the highest number of cases, already surpassing its total for all of last year. In Aichi, which has the second highest number of cases, a group infection has been confirmed at a high school. Reports of cases are particularly noticeable in major cities in prefectures such as Chiba, Kanagawa, Saitama and Osaka.

The increase is believed to be due to the spread of the virus brought in from abroad by people returning from overseas and the increase in the number of foreign visitors to Japan.

In 2015, Japan was certified by the World Health Organization as a country that had “achieved measles elimination.” However, as measles has recently been spreading globally, some countries, such as Britain and Canada, have had their certification revoked.

Measles spreads not only through direct contact or coughing and other forms of transmission by droplets, but also through airborne infection. People without immunity can become infected simply by being in the same room as an infected person. When an infected person is identified, it is necessary to minimize secondary infections.

Particular caution is necessary when an infected person has ridden a train or visited a supermarket, coming into contact with a large, unspecified number of people. Local governments should promptly disclose such information.

It is crucial for anyone suspected of contracting measles, due to symptoms such as a high fever or rash, to consult a medical institution by phone before visiting for an examination.

Although there is no specific treatment for measles, vaccination can prevent infection.

In Japan, those born in April 2000 and later are supposed to receive two routine vaccinations: one at age 1 and another before starting school. As a result, many young people are believed to have sufficient immunity. In addition, immunity lasts for those who have had measles.

On the other hand, people who have never had measles and have not been vaccinated are at high risk of infections. Even those who have received only one dose of the vaccine may have insufficient immunity.

Those who are concerned can visit a medical institution to undergo an antibody test to determine whether they have immunity.

Measles is often taken lightly because it has repeatedly spread domestically in the past, but it has claimed more than a few lives. Even today, it is estimated that one in 1,000 people who contract measles suffers severe cases and develops encephalitis. It is a life-threatening disease that must never be underestimated.

(From The Yomiuri Shimbun, April 2, 2026)