COLUMN

Author: Motoyoshi Okamura

2022/09/02

Many people took their children back to their parents’ homes during Obon, the first time in three years that there were no restrictions on travel. Many children must have made happy memories with their grandparents. Meanwhile, transmission of COVID-19 is spreading from the cities to the countryside. After the Bon Festival, the number of cases of COVID-19 infection is breaking records across the board in Kyushu, Shikoku, Tohoku, Hokkaido, and other regions where people returned home, and the unregulated return home has indeed led to an explosive spread of infection to the rural areas. Some experts believe that the restrictions  should have been continued, but at any rate, we must continue to wear masks, wash our hands, and refrain from going out to prevent further increase in the number of infected people.

●Antigen Testing Not Available

The number of new infections is reported every day, but how much of it reflects the reality of the situation? My daughter, who lives in Osaka, had a fever and asked the hospital for a test, but was refused because she was not seriously ill. She had no choice but to buy an antigen test kit at a nearby pharmacy, and when she tested negative, she tried to go to work, but was refused entry to the office and had to stay home for five days. 

The response to the test results varies from company to company, but more and more companies seem to be allowing employees to come to work when their fever is down and they can judge for themselves whether they can come in or not.

●We must understand that there will be new variants forever

Since the variant in trend is the Omicron variant worldwide and it has been detected by PCR tests and antigen test kits1), the current testing system should be sufficient for the time being to ascertain the number of infected persons, but the simple question of whether the test kits can detect new variants that may occur in the future remains unanswered.　

If large mutations in spiked proteins occur that cannot be detected by current testing methods, there should be a need to develop new testing kits.

Since medical institutions are no longer able to examine and treat newly infected patients in time, the government is reviewing the total number report and is changing its policy to a fixed-point report of only a portion of the number of infected patients. However, with the number of deaths still increasing, it is questionable whether they should stop reporting the total number of infected patients.

These questions arise only because we are forever concerned about the increase or decrease in the number of infected people.

●Can I use an antibody test?

If it is difficult to increase the number of tests even though the number of infected people continues to increase, and if clear measures cannot be taken to return to normal social life with peace of mind, it would be more effective to confirm that people are immune to COVID-19 than to determine whether or not they have contracted it, which would be a more effective measure for whether to restrict people’s actions.

Unfortunately, however, there are no antibody test kits approved as in vitro diagnostics as of August, although research antibody test kits, for which the reliability of the test is not guaranteed, are available at pharmacies. The key points for evaluation of antibody tests as indicated in Ref. 2) are

・”Antibody-positive” only indicates “high probability of having been infected in the past.”

・”Antibody present” ≠ “infection-protection immunity present.”

・Human immune responses vary widely from person to person.

In order to develop a diagnostic kit that can accurately determine “antibody positive” or “antibody negative” without being affected by individual differences, we still need to collect data on a large number of cases.

However, even the current antigen PCR test and antigen immunization test have results greatly influenced by individual differences. Many people do not take PCR and some people are “positive” and some are “negative” even after the same intense contact. Wouldn’t it be better to expand the use of “antibody tests” in combination with the current “antigen tests” to consider future trends and measures?