Himeji City, Hyogo Prefecture, announced that a new mutant virus called "BA.4" has been identified in one of the strains of the Omicron strain of the new coronavirus.

It is the second case that "BA.4" is confirmed in Japan except for quarantine, following Okayama prefecture.

According to Himeji City, on the 13th of this month, a woman in her 50s who had a feeling of malaise and headache was examined at a private laboratory, and an infection with the new corona was confirmed.

Symptoms are mild, he is being treated at home, and he has no history of traveling abroad.

When the Environmental Health Research Institute of Himeji City conducted a genome analysis, it was confirmed on the 23rd that it was a new mutant virus called "BA.4" in one of the strains of the Omicron strain.

"BA.4" was first detected in South Africa in January, and according to Himeji City, this is the second case following the first confirmation in Okayama Prefecture in Japan, excluding quarantine at the airport. That is.

According to the materials of the National Institute of Infectious Diseases dated June 3, there is no scientific evidence that "BA.4" has a large difference in severity compared to the conventional Omicron strain, but it should be monitored. It is said that it is necessary to continue.

Himeji City says, "We will continue to grasp the trends of mutant strains in the city and disclose information. Basic measures will not change even with mutant viruses, so we would like you to continue to thoroughly prevent infection."