Pharmaceutical company Takeda and the Japanese Ministry of Health said Thursday that Japan will discard 1.63 million doses of Moderna’s anti-virus vaccine after reports of contamination in several batches.

Takeda, which is responsible for selling and distributing the Moderna vaccine in Japan, said it had “received reports from various vaccination centers of foreign substances in sealed vials in specific batches.”

He added, “After consulting with the Ministry of Health, we decided to suspend the use of the vaccine from these doses, as of August 26.”

The company said it notified Moderna and requested an “urgent investigation.”

Moderna did not initially respond to a request for comment.

Confirmation did not specify the nature of the contamination, but said it had not received reports of health problems caused by the infected doses.

Japan’s health ministry said it will work with Takeda to obtain additional doses to avoid delays in Japan’s vaccination programme, which has accelerated after a slow start.

About 43% of Japan’s population is fully vaccinated, but the country is facing a strong outbreak of delta-variable infections, and many cities are under health restrictions.