Deputy Chief Cabinet Secretary Yoshihiko Isozaki tested positive for COVID-19 on Friday after showing symptoms including fever, TV network NTV said.
In the course of his job, Isozaki meets with Prime Minister Fumio Kishida relatively frequently, but the broadcaster gave no further details, including when the two of them last met.
Japan has seen a rapid surge in coronavirus cases, with the country topping 80,000 new cases on Friday, including over 17,000 in Tokyo.
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