In Tokyo, Japan, about 6% tested positive among volunteers for COVID-19 testing...

[Image source=EPA Yonhap News]

[Asia Economy Reporter Kwon Jae-hee] In Tokyo, the capital of Japan, antibody tests for the novel coronavirus infection (COVID-19) were conducted on volunteers, revealing that about 6% of the subjects possessed antibodies.

The presence of antibodies indicates past infection with COVID-19, suggesting the possibility that the virus has spread widely. Accordingly, calls have been made to further strengthen quarantine measures.

According to the Tokyo Shimbun on the 30th, antibody tests were conducted from the 21st to the 28th on 202 people at a hospital in Tokyo, including 123 men and 79 women, with 12 people, or 5.9%, testing positive.

Among the 202 tested, 55 were healthcare workers, of whom about 9.1%, or 5 people, tested positive. Among the remaining 147 general public, about 4.8%, or 7 people, tested positive.

Dr. Kusumi Eiji, an internist at the hospital conducting the tests, said, "It is highly likely that many more people have been infected than those identified by the current polymerase chain reaction (PCR) tests."

He added, "Considering the increasing number of unexplained deaths, PCR testing should be expanded to enable rapid diagnosis and early treatment."

Among the 202 people who underwent antibody testing, 52 had experienced fever symptoms within the past month, 2 had cohabitants confirmed with COVID-19, and 9 had previously undergone PCR testing to confirm infection status.

The antibody tests were conducted at two medical institutions in Tokyo, where Kusumi serves as director, recruiting volunteers via the internet. The reagent kits used were imported and sold by the Japanese textile company Kurabo.

Kurabo’s reagent kits are commonly used for antibody testing in Japan, and according to the Tokyo Shimbun, results can be obtained about 15 minutes after blood collection.

Recently, Keio University Hospital conducted PCR tests on 67 patients who visited the hospital for treatments other than COVID-19 before surgery or hospitalization, revealing that 4 patients, or about 6.0%, tested positive.

Keio University interpreted this as possibly reflecting the local infection situation.

The proportion of confirmed cases identified by PCR tests differs significantly from the infection rates found in the investigations by Dr. Kusumi and Keio University Hospital. However, since the sample sizes were small and the selection methods for subjects were specific, it is pointed out that simple comparisons with the proportion of confirmed cases in Tokyo identified by PCR tests are problematic.

Nevertheless, considering criticisms that PCR testing is insufficient and analyses suggesting that about 80% of infected individuals are asymptomatic or have mild symptoms, there is growing support for the analysis that confirmed cases in Tokyo represent only a very small fraction of the total infected population in the city.

Meanwhile, as of the 29th, the cumulative number of confirmed COVID-19 cases in Tokyo stands at 4,106, which is about 0.03% of Tokyo’s total population of 13,951,636 as estimated by the Tokyo Metropolitan Government as of January 1 this year.

This content was produced with the assistance of AI translation services.