Japan has in the last week suspended the use of 1.63 million doses of the Moderna COVID vaccine after discovering some vials were contaminated with stainless steel. Japanese officials reported on Wednesday that they believe that the stainless steel particles did not present a health risk. Moderna explained that the stainless steel fragments may have come from the machinery that places stops on the vials, which required the rubbing together of metals.

In a joint statement, Moderna and its Japanese partner Takeda Pharmaceutical Co. Ltd. said, "Stainless steel is routinely used in heart valves, joint replacements and metal sutures and staples. As such, it is not expected that injection of the particles identified in these lots in Japan would result in increased medical risk," Voice Of America reported.

It is estimated that about 500,000 individuals received shots from the batches of the Moderna COVID vaccine that were contaminated.

According to NTD, Moderna conducted its investigation into the contaminated COVID vaccines with the Spanish manufacturer Rovi, which operates the plant from which the contaminated vials originated. Rovi had undertaken a full inspection of its manufacturing facility and implemented new procedures to ensure similar problems do not happen again in the future.

Japan ordered to suspend the inoculation of Moderna COVID vaccines this week in three of its regions, as foreign substances were found in unused vials. Some of the cases were reportedly of bits of the vials' rubber stopper breaking off due to the incorrect insertion of needles into the vials.

A separate NTD report published on Wednesday revealed that Japan suspended another batch of Moderna COVID vaccines after a black material was found in one of the vials in Kanagawa prefecture, located south of Tokyo. Takeda said that 3,790 people were already inoculated with Moderna COVID vaccines from the suspended batch.

Meanwhile in the Gunma prefecture, similar concerns caused the suspension of COVID vaccine inoculation, but an official said that incolation will continue for those "lots that are not affected by the incident."

NTD reported over the weekend that two people have perished after they received Moderna jabs that came from the three contaminated batches of COVID vaccines. The report said that two men who were both in their 30's passed away in August just days after receiving their second dose of the Moderna COVID vaccine.

According to Bloomberg, both Moderna and Takeda said that there was no evidence to link their deaths to the stainless steel particles found inside the vials of COVID vaccines. In a joint statement released on Wednesday, the pharmaceutical giants said that the deaths were considered coincidental pending the conclusion of a formal investigation.

The investigation into the two deaths was launched by Moderna and Takeda, together with the Japanese Ministry of Health, Labour and Welfare (MHLW). The joint statement said that the investigation is "being conducted with the greatest sense of urgency, transparency and integrity and is of the highest priority" and that the companies are committed to keeping the public informed of any developments.