Virus mutations found in Japan might lessen vaccine effectiveness—researchers

TOKYO — Mutations that may reduce the effectiveness of COVID-19 vaccines have occurred in novel coronavirus samples collected from people in Japan last year, a research team from Keio University has found.

The mutation is believed to have occurred within the country, but there are no indications that the variant is currently spreading, the team said. The team’s members analyzed the genetic information of the virus that the National Institute of Infectious Diseases had registered in an international database. After the analysis, they found “E484K” mutations occurring in tips protruding from two viruses, which were collected in August and December last year.

Other than the mutated protruding tips, the genetic information was similar to that of the original virus that has been spreading across the country.

There are concerns that a E484K mutation might reduce the effectiveness of COVID-19 vaccinations as well as the antibodies that are produced in the body post-infection.

There have been cases in Japan where the E484K mutation was found in other mutated viruses such as the South African variant, but until now it was thought that all such variants had come from overseas.

“Mutations could continue to occur in Japan even in the future. It is important to be ready to quickly detect mutations such as E484K,” said Keio University professor and clinical geneticist Kenjiro Kosaki.