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Event title

Japan - Small measles outbreak in Japan raises alarm

Event category

Biological origin - Epidemic (human)



Event date (UTC)

2023-05-25 10:12:00

Last update (UTC)

2023-05-25 10:12:01





Area range

Multiple cities / districts wide event

Address/Affected area(s)

Tokyo and Ibaraki Prefecture

Officials in Japan are on high alert after a small outbreak of measles in Ibaraki Prefecture and Tokyo, with the situation taking on more urgency now that travel in and out of the country is returning to pre-pandemic levels.The latest three cases are evidence of how contagious measles can be, as it appears to have spread among strangers riding the same shinkansen for less than three hours.Among the infected patients is a man in his 30s who lives in Ibaraki Prefecture. The man developed a fever, cough and rash on April 21 to 23 after returning from a trip to India. Leaving Kobe on April 23, he took a shinkansen to Tokyo. He was diagnosed with measles on April 27 in Ibaraki.On May 3, two people — a woman in her 30s and a man in his 40s – both developed symptoms and later tested positive. They happened to be taking the same train as the Ibaraki man on April 23, the Tokyo Metropolitan Government said. The two Tokyo cases mark the first outbreak in the capital since 2020.
According to the health ministry, the virus can be transmitted by air, in droplets from an infected person's cough and by touching virus-infected surfaces. People who have no immunity to the virus are almost certain to develop symptoms if infected. Once infected, however, the immunity one develops is said to last for life.Measles has a typical incubation period of 10 to 12 days, though the period can be as long as 21 days. Officials urge people suspected of coming into contact with a measles patient to closely monitor their health for 21 days. Officials are also asking that people who suspect they may be infected avoid using public transportation and wear a mask when visiting a doctor.Symptoms start out as a fever, cough and a runny nose. A few days later, temperatures rise further — often exceeding 39 degrees Celsius — and a rash develops.Measles can be life-threatening — experts say it can lead to complications such as pneumonia or encephalitis — and has a death rate of one in 1,000 patients.There is no drug approved specifically for measles, but two shots of the measles vaccine can prevent the disease.However, many people born before Sept. 30, 1972, haven't been immunized for measles because Japan’s vaccine program started on Oct. 1 in 1978, targeting children between the ages of 1 and 6. Officials are urging people who have no history of infection and who have never been inoculated, or have received only one shot, to complete the two shots.In Japan, seven people have been confirmed so far this year as having been infected with measles. The country, which was recognized by the World Health Organization as having successfully eliminated endemic measles transmission in 2015, reported 744 cases in 2019, but cases remained low in recent years — 10 in 2020, six in 2021 and six in 2022 — due to the coronavirus pandemic, which severely restricted people’s movement both within Japan and internationally.

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