TOKYO -- COVID-19 infections will hit levels requiring yet another state of emergency even if all of Japan's elderly are vaccinated by the end of July, an analysis by a Japanese epidemiologist predicts.
Kyoto University professor Hiroshi Nishiura, a theoretical epidemiologist, submitted the analysis to the Ministry of Health, Labor and Welfare's advisory board on June 9.
The analysis assumes that coronavirus outbreaks at the same level as that which hit Osaka Prefecture during the fourth infection wave occur in Tokyo after the current state of emergency is lifted on June 20. It then estimates possible outbreak patterns and prospective demand for hospital beds designated for serious COVID-19 cases, on the premise that coronavirus inoculations for the elderly are completed by July's end.
According to the model, even if vaccination programs progress, the size of coronavirus outbreaks would be diminished only among older people, with no significant impact on the pace of transmission among those aged 0 to 59. Patients with severe COVID-19 symptoms would primarily comprise middle-aged people, and the number of infections would be about five times that of previous levels if the hospital bed occupancy rate remains about the same. This is because the proportion of patients who do not develop severe symptoms is higher among the middle-age group than the elderly.
Professor Nishiura said, "If countermeasures are taken by focusing solely on the number of serious COVID-19 cases, infection levels would grow, requiring a more than two-month state of emergency."
Regarding the potentially more transmissible L452R coronavirus variant initially found in India, Nishiura estimated its infectivity to be 1.78 times that of conventional strains. He forecasts that more than 50% of coronavirus cases in Japan would be attributed to that variant by mid-July.
At a June 9 meeting, the health ministry advisory board reported its analysis of the recent infection situation, with rising foot traffic in Tokyo in mind. "There are some areas where the rate of decline in infection numbers has been slowing down, indicating that case numbers may rebound," the board said.
According to the health ministry, 87 people were newly confirmed infected with the L452R in the past week, up 34 from the previous week.
(Japanese original by Sooryeon Kim, Lifestyle and Medical News Department)