Photo/Illutration Okinawa residents line up for free polymerase chain reaction tests at a site in Naha, the prefectural capital. (Minako Yoshimoto)

Okinawa is the only prefecture in Japan that reported a week-on-week decrease in new COVID-19 cases, but the virus has spread to more elderly people over that period, a health ministry advisory panel said.

For the week between Jan. 17 and 23, Okinawa Prefecture confirmed 8,289 new COVID-19 cases, a decrease from 9,355 reported in the previous week, the panel said at a Jan. 26 meeting.

Of the infected individuals whose ages were known, 698 were 70 or older between Jan. 17 and 23, a 1.6-fold increase from 437 in the previous week, according to an analysis by Yoshihiro Takayama, a physician at Okinawa Chubu Hospital and policy counselor on the crisis to the Okinawa prefectural government.

Conversely, the number of new patients between 20 and 39 decreased from 3,747 to 2,466 in the latest week in Okinawa Prefecture, he said.

The increased hospitalization ratio of senior citizens, who are more at risk of developing serious COVID-19 symptoms, is one factor behind the rapid filling up of hospital beds in Okinawa Prefecture.

The prefecture treated 25,172 patients for COVID-19 between Jan. 1 and 24. By Jan. 26, 2.4 percent of patients in their 40s were hospitalized, while 20 percent in their 70s and about 38 percent in their 80s were hospitalized.

Okinawa Prefecture still had the most new infections per 100,000 residents over the week ending on Jan. 25 with 554, exceeding the 513 of Osaka Prefecture and the 489 of Tokyo.

Japan had 444 COVID-19 patients with serious symptoms on Jan. 25, a 1.7-fold increase over the previous week.

According to the Cabinet Secretariat, seven prefectures had hospital bed usage ratios exceeding 50 percent as of Jan. 24.

Okinawa Prefecture had the highest ratio, at 62 percent. The prefecture also had an occupancy rate of 68 percent for hospital beds set aside for patients with serious symptoms.

(This article was written by Kayoko Geji and Senior Staff Writer Tokiko Tsuji.)