TOKYO -- The number of people found infected with new strains of the coronavirus in Japan has topped 100, with community infections reported and major clusters seen in Saitama Prefecture, north of Tokyo.
The World Health Organization (WHO) said that one variant was up to 70% more transmissible than the original, and experts in Japan are calling for people to be careful.
The first variant cases were detected on Dec. 25 last year at Haneda Airport in the capital, and Kansai International Airport in western Japan. Then on Jan. 18, three people who'd had no contact with people who returned from overseas were confirmed to have been infected in Shizuoka Prefecture in what were believed to be cases of community transmission.
On Feb. 10, three more infections were confirmed in Hyogo Prefecture, bringing the total infected with new strains of the virus to 108. Of these, 43 cases were detected in airport quarantine, while there were 51 suspected cases of community transmission in Tokyo and 10 other prefectures. The remaining 14 cases were confirmed among those who had stayed in other countries and people who were connected to them. Ninety-three people were infected with a variant from Britain, 11 with one from South Africa, and four with one from Brazil.
In Saitama Prefecture, two variant strain clusters have already been reported. In the first report, 11 people including at least one worker at a day care center and a number of children at the center under the age of 10 were infected. The other cluster is believed to have spread from a workplace.
However, because the community infections in Shizuoka Prefecture did not result in variant clusters, a senior official at Japan's Ministry of Health, Labor and Welfare commented, "At the current stage we cannot determine whether the variants are more transmissible than the original."
By Jan. 21, around 18,000 samples had been analyzed, and at a Feb. 10 news conference, Chief Cabinet Secretary Katsunobu Kato commented, "In almost all of the (variant) cases, we've been able to trace the (infection route) links. As it stands, infections with the variants are not occurring under circumstances where there are no links in the community at all."
According to the WHO, the virus variant from Britain had been found in 86 countries as of Feb. 8, while the one from South Africa had turned up in 44 countries, and the threat is spreading around the world.
It has been pointed out that the variant from Britain may increase the risk of death. However, the BBC reported on Feb. 9, "There has been some suggestion that the strain may be associated with a 30% higher risk of death, but the evidence on this is not strong, and the data is still uncertain."
In the United States, the Centers for Disease Control and Prevention stated, "In January 2021, experts in the UK reported that this variant may be associated with an increased risk of death compared to other variant viruses, but more studies are needed to confirm this finding."
Last year, U.S. magazine Newsweek quoted a scientist as saying that during an England-wide lockdown from Nov. 5 to Dec. 2, there was a statistically significantly higher proportion of cases of the variant in those under the age of 15 -- suggesting the new strain may spread more easily among children. The British journal Nature, meanwhile, cited a January report from Public Health England which said it was thought that the variants spread easily across all age groups.
At the same time, there have been moves to put off the start of COVID-19 vaccinations with the AstraZeneca vaccine over the possibility that it could be less effective against variants of the virus like the one from South Africa.
Experts in Japan are divided over the issue. One expert providing advice to the Ministry of Health, Labor and Welfare regarding coronavirus countermeasures commented, "The new variants are enough to send our countermeasures and knowledge up to this point back to the drawing board."
Tetsuya Matsumoto, a professor at the International University of Health and Welfare who specializes in the study of infectious diseases, commented, "In Saitama, we saw clusters of considerable numbers of people, and it appears that the variant is highly infectious. We fear that it may spread among young adults going forward."
However, Koichi Morita of the Institute of Tropical Medicine at Nagasaki University commented, "The new variant is not yet spreading in Japan. Its high infectiousness has been announced in the U.K., but that also needs to be verified in Japan."
(Japanese original Naomi Hayashi, Yuki Ogawa and Sooryeon Kim, Lifestyle and Medical News Department)