Japan to conduct 10,000 coronavirus antibody tests

TOKYO - Japan aims to test around 10,000 people across the country for coronavirus antibodies from next month, to help authorities understand the extent of the spread of the pneumonia-carrying virus, Health Minister Kato Katsunobu said Friday.

Katsunobu said that by conducting large-scale tests of antibodies, health officials would potentially be able to gain a better understanding of how much of Japan's population has been infected by the coronavirus.

He said that as many as 10,000 tests could begin as early as June before being ramped up, with antibodies from people being collected from the hard-hit prefectures of Tokyo and Osaka, as well as Miyagi Prefecture, where the number of COVID-19 cases has been relatively low.

The tests, which provide indicators on unique proteins made by a person's immune system after they have been infected with the virus, will also help authorities better understand how many people will require vaccinating once one becomes available, as well as an idea of the severity of the situation should further waves of the pandemic hit Japan.

The tests will also help to determine the level or possibility of Japan's "herd immunity," which is achieved when a large percentage of the population develops antibodies and potential immunity to a virus.

The antibody tests use blood samples and produce results faster than polymerase chain reaction (PCR) tests. Some experts have voiced concern, however, that some of the trial antibody tests conducted here as well as overseas have produced inaccurate results.

In April, the health ministry screened for antibodies in experimental tests with donor blood from Tokyo and six prefectures in northeastern Japan, where the ministry used test kits from five firms to conduct provisional experiments.