Measles Outbreak Feared in Japan

Yomiuri Shimbun file photo
A boy receives a measles vaccination in Shibuya Ward, Tokyo.

TOKYO (Jiji Press) — Experts are calling on people to get vaccinated against measles, citing concerns about a possible outbreak as travel between Japan and abroad is becoming active again after COVID-19 restrictions were lifted.

In Japan, where there is no indigenous measles virus, 10 infection cases had been reported this year as of May 28, according to the National Institute of Infectious Diseases. Experts pointed to the possibility of infections with the virus from foreign countries.

The measles virus is transmitted mainly through the air and droplets. After an incubation period of about 10 days, infected people develop a fever and cough, followed by a high fever and rash. The virus may cause pneumonia.

There is no specific treatment for the disease. Even in developed countries, one in 1,000 people may die from it.

Japan had more than 10,000 measles cases in 2008. But the number plummeted to 35 in 2015 due to increased vaccination opportunities. Later, the World Health Organization recognized that there is no indigenous measles virus in the country.

The introduction of border control measures during the COVID-19 pandemic helped to reduce the number of measles cases in Japan to 10 in 2020 and six each in 2021 and 2022. This year, however, 10 cases were reported only in the first five months.

The risk of an influx of the virus will increase further as the number of people traveling to and from Japan increases after the border controls were lifted.

In April, a man in Ibaraki Prefecture developed measles symptoms after returning from India. A man and a woman in Tokyo who were in the same Shinkansen bullet train with him later tested positive for the virus.

Vaccinations are most effective in preventing measles infections. In Japan, people have opportunities to be inoculated against the measles virus at 1 year of age and before entering elementary school.

The rate of people who had received a second dose came to 93.8% in fiscal 2021. The proportion has been on a declining trend apparently because people refrained from seeing a doctor during the COVID-19 pandemic.

“The number of patients is expected to increase further, but there is no need to panic,” said Fumio Ota, director of Ota Kids Clinic in the city of Chiba. “We want [children] to receive [vaccines] twice without missing the opportunities.”