A Kyoto University research team has announced their finding that the percentage of severe COVID-19 cases declined significantly during the June-August quarter compared with the January-April quarter. The university made the announcement at a meeting of an expert panel under the Ministry of Health, Labor and Welfare (MHLW) on Oct. 22. The reason for the drop is likely early detection and improved medical treatment.

Professor Hiroshi Nishiura of Kyoto University calculated the percentage of severe COVID cases out of all cases based on data provided by the MHLW. Serious cases made up 9.80% of all cases in the January-April quarter but only 1.62% in the June-August quarter. By age, the percentage of patients in their 40s who developed severe symptoms decreased from 3.43% to 0.54%; patients in their 60s, from 15.25% to 3.85%; and patients in their 80s, from 34.72% to 14.5%. National Institute of Infectious Diseases Director-General Takaji Wakita, who chairs the panel, warned, “Although the percentage of severe cases declined, it remains high for the elderly. If the number of cases were to increase, it could still be a very difficult situation.”

The expert panel concluded that the nationwide COVID situation has been moving from mostly flat to slightly increasing. At various monitoring locations, the effective reproduction number has stayed at approximately 1 since September, indicating that the situation will stay the same. Tokyo, however, had an effective reproduction number of 1.64 on Oct. 5, suggesting that the infection was about to spread. The panel warns that the infection situation still remains delicate.