Indian variant may have entered Japan via U.K., U.S.

Possibilities are high that the so-called Indian variant of the novel coronavirus entered Japan not only from India but also via Britain and the United States, according to an analysis by researchers at Keio University.

Kenjiro Kosaki, a professor of clinical genetics at the university who took part in the analysis, said it is important to strengthen border controls to stop the influx of the virus into Japan from countries other than those considered to be the pandemic area.

The Indian variant, now being referred to as the “Delta variant” by health organizations, is said to be highly infectious and has been reported in more than 60 countries. According to the Health, Labor and Welfare Ministry, the number of people identified as being infected with the Indian variant, not counting those confirmed at airport quarantines, was 53 as of May 31.

Using an international database of the genetic information about viruses, the team compared the genetic details of the Indian variant detected in 18 people identified as infected in Japan with that of variants found overseas.

As a result, five types of Indian variants were found to have entered the country from India, three via Britain, and one via the United States.

Tetsuya Mizutani, a professor of virology at Tokyo University of Agriculture and Technology, said: “Virus variants can enter the country by slipping through quarantine. Analyses like the latest one will provide clues as to how quarantines should be strengthened.” (June 9)