Photo/Illutration The Tokyo metropolitan government building (Asahi Shimbun file photo)

Around 18,000 COVID-19 cases in Chiba Prefecture have been included in Tokyo’s total for new infections since July 23, the Tokyo metropolitan government said on Aug. 16.

Under the infectious diseases prevention law, medical institutions must notify health care centers about confirmed novel coronavirus infections.

Chiba Prefecture and Noda city in the prefecture outsource such reporting to medical institutions, but they are located in Tokyo. These institutions reported the COVID-19 cases in Chiba Prefecture to health centers in Tokyo.

As a result, 17,946 COVID-19 cases received at a registration center in Chiba Prefecture since July 23 and 86 cases in Noda city were reported to health care centers in Tokyo, the metropolitan government said.

These cases were not reported in Chiba Prefecture, so there was no overlap in the neighboring prefectures’ infection tallies, according to the metropolitan government.

Registration centers run by local governments accept online applications from people who test positive using self-test kits. The centers then submit notifications of the positive cases to health care centers after checking details of the applications.

The number of new COVID-19 cases reported by the metropolitan government also included people living outside of Tokyo who tested positive at medical institutions in the capital.

Authorities investigated after a large number of residents in Chiba Prefecture were found included in Tokyo’s tallies after July 23.

The metropolitan government said it will continue to provide overall numbers of new COVID-19 cases, including patients in Chiba Prefecture.

But from Aug. 17, it will also release numbers that exclude the counts at registration centers in Chiba Prefecture and Noda city.