Contaminant in Moderna COVID-19 vaccine vials found in Japan was metallic particles: report

Moderna manufacturing site
Japan has suspended the use of 1.63 million doses of Moderna's COVID-19 vaccine. (Moderna)

Moderna is getting more clarity on the contamination in vials of its COVID-19 vaccine that were discovered in Japan. 

The contaminant is believed to be a metallic particle, said Japanese public broadcasting outlet NHK, citing health ministry sources.

Wednesday, Takeda, Moderna’s COVID-19 vaccine partner in Japan, suspended the use of 1.63 million doses that had been distributed to 863 vaccination centers in the country. Contaminants were found in vials of one lot, and, as a precaution, Moderna said it put two adjacent lots on hold.

The suspension of the doses comes as 80% of Japan's population is under coronavirus restrictions. 

RELATED: Moderna probes reports of COVID-19 vaccine contamination in Japan

Moderna has traced the issue to a production line in Spain, where one of its manufacturing partners produces the vaccines. In a regulatory filing Thursday, the biotech's Spanish production partner, Rovi Laboratories, said the contamination was limited to the one product lot bound for Japan. The company added it is investigating the issue and is in communication with health authorities in Japan.

The particulate matter, whose composition has not been determined, was discovered in roughly 40 unused vials across eight vaccination sites in Japan, NHK reported. Japan’s chief cabinet secretary, Katsunobu Kato, told reporters that contaminated doses were administered to an unspecified number of people.  

Moderna said it hasn't identified any safety concerns, and it has not received any reports of adverse reactions among vaccine recipients.

RELATED: Moderna inks fill-finish pact with Spain's Rovi for 'hundreds of millions' of COVID-19 shot doses

In June of 2020, Rovi signed on to produce Moderna's COVID-19 vaccine. In April, the company revealed that it would begin producing bulk drug substance—in addition to bottling doses—from its plant in Grenada, Spain. Previously, the manufacturer received active vaccine ingredient from Switzerland.

Compared to manufacturing problems that have hampered COVID-19 shots made by Johnson & Johnson and AstraZeneca, it’s been a relatively smooth ride for Moderna’s vaccine rollout. The company expects to make $19 billion in sales of the vaccine this year.