Rise in Measles Patients: Pay Close Attention to Outbreaks Overseas

Editorial

16:20 JST, April 27, 2025

With the number of measles patients rising worldwide, there has also been a spate of cases reported in Japan. Caution is needed, as people now travel between Japan and overseas destinations more frequently.

A total of 78 measles cases have been confirmed in Japan so far this year, already exceeding the number for all of last year, which was 45.

In 2015, Japan was recognized by the World Health Organization as a country that had eliminated measles virus through widespread vaccination efforts. Nevertheless, the number of measles patients has climbed again, and this appears to be chiefly attributable to visitors who brought measles into Japan from countries where the disease is prevalent.

In half of the measles cases reported this year, patients are believed to have been infected in foreign countries, such as Vietnam and Thailand.

Some people are likely planning overseas trips during the extended holiday period. In addition to Asian countries, the disease has also been rampant recently in some areas of the United States. People planning to travel abroad are encouraged to keep an eye on information provided by the Health, Labor and Welfare Ministry regarding the measles outbreaks in such countries.

With the number of foreign visitors to Japan increasing, the risk of measles being brought into Japan has also climbed. As the Osaka-Kansai Expo has started and is attracting people from both Japan and abroad, this could also accelerate the spread of infection. It is essential for society as a whole to strengthen its vigilance.

Measles is highly contagious because it can be transmitted through the air. People can catch the disease simply by being in the same room as an infected person. After an incubation period of 10 to 12 days, measles patients develop symptoms such as fever and a rash. In severe cases, measles can cause pneumonia or encephalitis, which can be life-threatening.

People who have had measles are presumed to have lifelong immunity. In Japan, outbreaks of measles used to occur repeatedly, therefore many people in their 50s and older are likely to have been infected previously.

In addition, people born in 2000 or later have received two doses of the measles vaccine — one at the age of 1 and another before entering elementary school — through the standard immunization program. They are thought to have sufficient immunity.

People who have never had the measles and those who have received only one dose of the vaccine are a source of concern. There was a time when the vaccination program provided only one dose of the vaccine.

It is important for people to undergo testing at a medical institution to determine if they have antibodies and receive the vaccine if necessary, for example before they travel to destinations where a measles outbreak is occurring.

However, vaccines made by a certain company have been suspended due to insufficient preventive effects, a situation that has disrupted supply. The government should work with other vaccine makers and relevant entities to ensure that the production and distribution of the vaccine is not disrupted.

People who have traveled to countries where there are measles outbreaks should pay attention to their health for about two weeks after returning to Japan. If symptoms such as a rash appear, they should first contact a medical institution by phone and seek a doctor’s examination.

(From The Yomiuri Shimbun, April 27, 2025)