Speaking to reporters on Thursday, the chief cabinet secretary, Katsunobu Kato, said that an unknown number of people had been vaccinated with the contaminated doses, but that the government had received no reports of ill effects. He urged people with concerns to consult their doctors.
After getting off to a slow start, Japan is now administering over a million vaccine doses each day. Currently, about 43 percent of the population is fully vaccinated. In addition to Moderna, Japan has approved the use of vaccines produced by Pfizer and AstraZeneca.
However, as the inoculation program has accelerated, so has the virus. Tokyo declared its fourth state of emergency in July as it confronted a rapid rise in cases driven by the Delta variant. The situation has since deteriorated rapidly, with daily case numbers reaching over 25,000 for the first time on Friday. Total deaths are at nearly 15,700.
The decision to withdraw the Moderna doses is not expected to have a major impact on the overall vaccination program, Mr. Kato said, adding that the government was working to reduce any disruptions.
Despite the rising numbers, Tokyo has carried on more or less as usual. The city is currently hosting the Paralympics, which opened on Tuesday.