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Early treatment needed as medicines less effective against omicron subvariant: Osaka doctor

Osaka City Juso Hospital director Osamu Kurai is seen speaking about issues ahead of a potential resurgence in COVID-19 cases at the hospital in the city of Osaka's Yodogawa Ward on April 11, 2022. (Mainichi/Mirai Nagira)

OSAKA -- A hospital doctor here has stressed the need for early-stage treatment of COVID-19, noting continuing high infection numbers and the lower effectiveness of some medicines in recent cases.

    The Japanese government has expressed the view that some medications will be less effective against the BA.2 omicron subvariant that has already become mainstream in Japan.

    Osamu Kurai, the 61-year-old director of Osaka City Juso Hospital, which has 70 beds set aside for patients with moderate COVID-19 symptoms, said, "During the sixth wave, there were issues where in some cases, the time between the onset of symptoms and hospitalization became prolonged, and the necessary medicine could not be used."

    The hospital said it provided care for 336 hospitalized patients between Dec. 1, 2021 and April 15, 2022, during the sixth coronavirus wave. Of medicine that could be used for patients with mild or moderate symptoms, IV-administered remdesivir, an antiviral medication that inhibits the replication of viruses, was given to 102 patients, while the antiviral drugs molnupiravir and nirmatrelvir/ritonavir, which are taken orally, were administered to 50 and five people, respectively. The neutralizing antibody medication sotrovimab, which is administered intravenously and prevents viruses from entering into cells, was given to 138 patients -- the largest group.

    All aforementioned drugs need to be used within five to seven days from the onset of symptoms. At Juso Hospital, three male patients in their 70s developed severe symptoms amid the sixth wave, and were transferred to a hospital that deals with serious cases. For each of these cases, the patients were hospitalized after their symptoms worsened as seven days or more had passed since they developed symptoms, and the applicable medicine could apparently not be administered. At the time, over 10,000 COVID-19 cases had been confirmed on a daily basis in Osaka Prefecture, and it seems that the rise in infections, which exceeded public health centers' capacity to arrange hospitalizations, led to delays.

    It is possible that there will be fewer medication options during the seventh coronavirus wave. The Ministry of Health, Labor and Welfare decided to warn that sotrovimab, which was effective against earlier coronavirus variants, may have weaker efficacy against the BA.2 omicron subvariant. Meanwhile, the efficacy of antiviral medication including remdesivir is said to remain the same.

    Kurai commented, "During the next surge of infections, antiviral medication will play a central role. A medical system that makes it possible for patients to immediately receive treatment once they are diagnosed with COVID-19 will have increasing significance."

    (Japanese original by Mirai Nagira, Osaka Science & Environment News Department)

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