Over 80% of Tokyo infections linked to variants

The Japan News
Tokyo metropolitan government office

Infectious coronavirus variants such as the one first detected in Britain account for over 80% of all new cases in Tokyo, according to metropolitan government data. With crowds returning to central areas of the capital and no significant decline in the number of cases, experts have warned of another possible spike in infections.

At a metropolitan government COVID-19 meeting on Friday, Norio Omagari, director of the Disease Control and Prevention Center of the National Center for Global Health and Medicine, said, “Considering the effects of the more infectious variants, a rapid resurgence is feared in the future.”

According to the Tokyo government, of 2,300 samples tested from May 17 to 23 at the Tokyo Metropolitan Institute of Public Health and other facilities, variants with the N501Y mutation such as the British variant accounted for a record 1,899 cases, or 82.6%, exceeding the 81.5% reported in the previous week.

Compared to the original virus, the British variant is estimated to be 1.3 times more infectious and 1.4 times more likely to develop into severe disease.

The number of people going out has been increasing in Tokyo. According to the Tokyo Metropolitan Institute of Medical Science, foot traffic in central Tokyo districts in the week through May 29 was up 25% at night and up 19% during daytime hours compared to the week through May 8, during which the lowest foot traffic was seen since the declaration of the third state of emergency.

Atsushi Nishida of the institute’s Research Center for Social Science & Medicine Sciences said, “The number of people going out has continued to increase since the extension of the state of emergency. Infections are more likely to spread again.”

Doctors and public health center directors are increasingly concerned about the infectiousness of the variants.

Ikebukuro Otani Clinic Director Yoshio Otani, a doctor of respiratory medicine who treats coronavirus patients, said, “Patients have been infected with variants even though they wore masks, which suggests that it is highly infectious.”

Since April 28, his clinic in Toshima Ward, Tokyo, has had samples from coronavirus patients tested to check for variants. Of the 31 coronavirus patients treated at the clinic, 29 were infected with variants that had the N501Y mutation. The ages of the patients ranged from 5 to 65, and 11 were in their 20s, making up the largest proportion.

Infection clusters

According to the Sumida ward public health center, infection clusters linked to variants occurred at a nursing care home and a medical institution in the ward.

At the nursing home, infection prevention measures included social distancing, with seating arranged one to two meters apart, and acrylic boards on dining tables to prevent droplets from spreading.

However, a cluster was identified 24-48 hours after the first infection was detected at the facility.

“One of the characteristics of the variant is that it spreads in a short amount of time, so we need quicker responses,” the director of the public health center said.

The Yomiuri Shimbun