Foreign substance detected in Moderna vaccine in Japan may be metal

The foreign substance was identified in 39 unused vials, all of which had the lot number 3004667, at eight workplace and large-scale inoculation sites in five prefectures — Aichi, Ibaraki, Gifu, Saitama and Tokyo — with the first discovery having come on Aug. 16. The government on Thursday decided to halt the use of vials belonging to that lot number — as well as those with the lot numbers 3004734 and 3004956, which were produced around the same time and at the same facility — affecting a total of 1.63 million shots.

More than 187,000 shots from the three suspended lot numbers had already been administered in at least 21 prefectures, according to a tally by Kyodo News. Those include 50,000 doses in Osaka, 41,500 in Hyogo, 28,020 in Aichi and 13,330 in Hiroshima.

The vials in question were made by Laboratorios Farmaceuticos Rovi, which has been handling the final step in the manufacturing process for Moderna vials using vaccine ingredients produced in Switzerland that are destined for markets outside the U.S. The Spanish pharmaceutical firm said Thursday that the one product lot in which the foreign substance has been detected was distributed exclusively in Japan, adding that it may have originated from one of the company’s production lines.

An investigation by Moderna, Rovi and Takeda Pharmaceutical Co., which is in charge of the vaccine’s distribution in Japan, is ongoing. The foreign material is “a metal that reacts to a magnet” and is believed to have entered the vials during the production process, the Asahi Shimbun quoted an unidentified senior health ministry official as saying.

So far, there have been no reports of ill health from contaminated doses, or of foreign materials in other batches of the Moderna vaccine that have been distributed in Japan.

The risk that a contaminated vial would be administered is seen as low by experts, as the standard protocol is to check for any abnormalities before use.