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Experts poke holes in Japan's COVID measure 'verification tests'

People at Toyota Stadium in Toyota, Aichi Prefecture, present proof of vaccination or a negative PCR test before picking up tickets to a soccer match on Oct. 6, 2021. (Mainichi/Takumi Hosoya)

TOKYO -- The Japanese government launched verification tests for its coronavirus transmission prevention measures across Japan on Oct. 6. And though the results will be treated as a litmus test for allowing the full-fledged loosening of pandemic restrictions, several potential problems have already surfaced.

    The Japanese government has high hopes that the verification techniques will reduce infection risks. However, their efficacy has limits, and if they are deployed incorrectly, observers have pointed out they could lead to secondary spread.

    The main pillar of the policy is the "vaccine and test package." At restaurants and bars, this means checking if customers have a COVID-19 vaccination certificate or asking them to submit to a virus test before allowing them in. However, Tohoku University public health professor Ken Osaka told the Mainichi Shimbun, "While doing this is better than not doing it, it won't be the brake on infections that people are expecting."

    There is research showing that the efficacy of two shots of the Pfizer vaccine drops by about half after six months, and some countries have put expiry dates on their vaccine certificates. Based on this, Osaka is calling on Japan to also add an expiry date.

    The government has indicated that PCR coronavirus test results -- which are very precise -- are valid for 72 hours, and the simpler antibody test results for 24 hours. However, this relies on the individual being truthful about when the test sample was taken, or even that the sample was theirs at all. Antibody tests, meanwhile, are not recommended for asymptomatic cases with low virus particle counts, and can fail to detect infected people.

    One prefectural official in charge of verification said they can't expect people to spend thousands of yen on a coronavirus test before going into a restaurant. "How many people are going to get an antibody test outside the restaurant and then wait around for some dozens of minutes for the result before they can go in?" they said. "Places doing the verifications may lose customers."

    There are also problems with some of the other verification techniques. The central government has told local authorities that it will examine the efficacy of CO2 concentration meters and partitions on transmission. If an interior space is badly ventilated, then the concentration of CO2 in people's breath rises, so the government has encouraged the installation of CO2 meters to monitor ventilation.

    However, when specially appointed associate professor Yo Ishigaki of the University of Electro-Communications in Tokyo tested 12 CO2 monitors priced at 5,000 yen (about $45) or less, he found that nine of them failed to detect the gas at all, and some even malfunctioned. The remaining three models gave inaccurate readings. At a nursing home hit by a COVID-19 cluster in April this year, it was later found that none of the CO2 monitors at the facility had picked anything up.

    The central government is also recommending that locales such as restaurants and bars put in acrylic partitions to block aerosol droplets from people's mouths from reaching others. Ishigaki, though, points out that installing very large partitions worsens air circulation in the room.

    "It's not enough just to have CO2 sensors and acrylic partitions," he told the Mainichi Shimbun. "I'd like to see the national government verify the installation procedure and other aspects, and put together guidelines on appropriate ventilation."

    (Japanese original by Hiroyuki Harada and Takashi Kokaji, Lifestyle & Medical News Department)

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