Photo/Illutration Mask-wearing visitors walk along the Nakamise shopping street in Tokyo’s Asakusa district on Dec. 14. (Nobuo Fujiwara)

Following record-high numbers the previous week, Tokyo reported 556 new novel coronavirus cases on Dec. 20, the first time in five days the daily count dropped below 600, metropolitan officials announced.

Of the new cases, 150 patients were in their 20s, more than any other age group, followed by 111 patients in their 30s and 92 patients in their 40s.

While 61 patients were in their 50s, those 65 or older, who are at high risk of developing serious symptoms, totaled 73.

The number of serious cases rose to 66, up four from the day before. The metropolitan government defines serious cases as patients requiring ventilators or an extracorporeal membrane oxygenation (ECMO) device, which circulates blood through an artificial lung.