Mass coronavirus infections are suspected to have occurred at two music clubs in Osaka last month.

A total of 39 infections in 13 prefectures across the country had been reported as of Friday in connection with events at Osaka Kyobashi Live House Arc and Soap Opera Classics Umeda.

About 220 people attended an event at the former from Feb. 15 to 16, while an event at the latter was attended by about 180 people between Feb. 19 and 23, according to the Osaka Prefectural Government.

Suspicions of a mass infection at Osaka Kyobashi Live House Arc first arose on Feb. 29, when a woman in her 30s in Kochi was confirmed to have the virus. She had been complaining of a sore throat before the event.

It was learned later that a man in his 30s in the city of Osaka attended both events in question.

The health ministry’s infection cluster response team opened an investigation into the suspected mass infections on Monday at the request of the Osaka Prefectural Government.

The prefectural government is calling on those who attended the music events to report to public health centers in their neighborhoods and plans to monitor their health for three weeks.