COVID-19 Cases up for 8th Consecutive Week in Japan; Omicron Subvariant Nimbus Accounts for About 40% of Infections

The Yomiuri Shimbun

14:19 JST, August 16, 2025

The number of people infected with COVID-19 has increased for eight consecutive weeks, driven by the spread of a new coronavirus subvariant.

The Health, Labor and Welfare Ministry announced Friday that the number of people infected with the virus, based on reports from about 3,000 medical institutions designated for surveillance from Aug. 4 to 10, was an average of 6.13 people per institution, 1.11 times higher than the previous week’s 5.53 people.

On a prefectural basis, the highest figure was reported in Miyazaki Prefecture, with 14.71 people per institution, followed by Kagoshima Prefecture with 13.46 people and Saga Prefecture with 11.83 people, putting the Kyushu region at the top of list.

This summer, spread of an omicron subvariant known as nimbus has been high. The latest data released in July by the Japan Institute for Health Security shows nimbus accounted for about 40% of infections in Japan. One of its more noticeable symptoms is said to be severe sore throat.

Increased movement of people during the Bon holidays may have led to a greater risk of infection.

“We need to stay cautious about an increase in infections,” said Nobuhiko Okabe, an advisor at the Kawasaki City Institute for Public Health. “It is particularly important for people to wear masks if necessary, as well as washing hands and maintaining good ventilation.”

As more time passes after vaccination, susceptibility to infection increases, and elderly people are more likely to develop severe symptoms.

Prof. Hiroyuki Kunishima of St. Marianna University School of Medicine said, “I recommend elderly people go to medical institutions to prevent severe illness even when in the absence of noticeable symptoms like fever.”