Japan’s government says it has identified new, more contagious coronavirus variant

Japan has confirmed the discovery of a new, more contagious coronavirus variant, according to a report released by the country’s National Institute of Infectious Diseases (NIID).

Reuters reported that the new strain appears to have originated overseas, but is different than the other strains identified in Britain, South Africa and Brazil.

"It may be more contagious than conventional strains, and if it continues to spread domestically, it could lead to a rapid rise in cases," Chief Cabinet Secretary Katsunobu Kato said Friday, Reuters reported.

According to the NIID report, 91 cases of the new strain have been identified in the Kanto region of Japan, roughly 64 miles north of Tokyo. 

The discovery of the new strain comes as Japan approved and began administering its first COVID-19 vaccine on Sunday. Japan’s health ministry said it had approved the vaccine co-developed and supplied by Pfizer.

Many countries began vaccinating their citizens late last year, and Pfizer’s vaccine has been used elsewhere since December.

Under the current vaccination plan, about 20,000 front-line medical workers at hospitals in Japan will get the first shots. About 3.7 million other medical workers will be next, followed by elderly people, who are expected to get their shots in April. By June, it’s expected that all others will be eligible.

The NIID report published Friday acknowledges the beneficial timing of the nation’s vaccine approval but urges medical experts to be on the lookout for adaptive mutations of the virus, suggesting the establishment of systematic genome surveillance. 

So far, there has been no evidence to suggest that the current COVID-19 vaccines wouldn’t work against the other mutations identified around the world.

But a separate laboratory study from Pfizer Inc-BioNTech suggests that the company’s current COVID-19 vaccine may generate a significantly less robust antibody response against the South Africa variant of the coronavirus. 

According to the in-vitro study published in the New England Journal of Medicine (NEJM), lab results "indicated a reduction in neutralization," of the virus.

Japan’s NIID pointed to the same possibility in its report. 

"It has been pointed out that the mutant [South African] strain has the possibility of immune escape that increases the transmission power and diminishes the vaccine effect," The NIID report read. 

RELATED: Pfizer says lab test indicates diminished antibody response by its COVID-19 vaccine to South Africa variant

In the Pfizer study on the South Africa variant, researchers analyzed blood from people who had taken the Pfizer coronavirus vaccine and identified a two-thirds reduction in the level of neutralizing COVID-19 antibodies to the South Africa variant. 

This was compared with the most common variant of the virus prevalent in the U.S. 

"It is unclear what effect a reduction in neutralization by approximately two-thirds would have on BNT162b2-elicited protection from Covid-19 caused by the B.1.351 lineage of SARS-CoV-2," researchers wrote.

Despite the results of the in vitro lab test, the company said that there is still no clinical evidence from human trials that the South African mutation reduces the overall protection of the vaccine.

The Associated Press contributed to this story.