Another 1M Moderna coronavirus vaccine doses halted in Japan as officials probe 2 deaths

Moderna manufacturing site
Two men in Japan, both in their 30s died after receiving a second dose of the Moderna vaccine from a lot where contaminants had been identified. (Moderna)

Manufacturing issues and safety concerns have unraveled the best-laid plans for COVID-19 vaccine makers AstraZeneca and Johnson & Johnson. Now, it’s Moderna facing serious questions about its vaccine after two people in Japan died after receiving the shot from a contaminated batch.

No link between the vaccine and the fatalities has been established, Moderna said in a joint statement with its Japanese COVID-19 vaccine distribution partner Takeda. But over the weekend, another one million doses of the vaccine were suspended over concerns of possible contamination found in two additional vaccine lots.

Over the last two weeks, contaminants were found in approximately 40 unused vials from the same lot. The material was determined to be metallic particles, Japan news outlet NHK reported last week. Last week, Japan suspended the use of 1.63 million doses.

In Gunma prefecture northwest of Tokyo, a black substance was found in a Moderna vaccine vial, The Japan Times reported. In Okinawa, south of the mainland, a black substance was found in syringes and a vial, while a pink substance was found in another syringe. 

Incorrect insertion of needles into vials could account for the recently discovered foreign material, Japan’s health ministry said. Other vials from the lot could continue to be used, the ministry said.

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

“At this moment, we will not make further comments to the media until the investigation is completed and there are solid conclusions,” a Rovi spokesperson wrote in an email.

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

The two Moderna vaccine recipients who died were men aged 30 and 38, The Japan Times reports. Both had received two doses of the vaccine.

“At this time, we do not have any evidence that these deaths are caused by the Moderna COVID-19 vaccine and it is important to conduct a formal investigation to determine whether there is any connection,” Moderna and Takeda said in an emailed statement. 

Japanese infectious disease expert Takeshi Terashima cast doubt on the possibility that the contamination could have caused the deaths.

“The risk that the foreign material causes some kind of a disease at the spot where it was injected or that it circulates in the body’s blood and causes a disease after an intramuscular injection through a 0.25-millimeter needle would be extremely unlikely,” he told Japan’s TBS News.

Masayuki Miyasaka, professor immunology at Osaka University, added on Facebook that “there is a near zero chance” of a “minute piece of metal” causing substantial health damage.

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

Moderna is working with Rovi to determine the “precise nature” of the contaminant, it said. Lab analysis on the vials is underway. Moderna said it expects results to be available early this week.

The news comes as Japan battles a delta variant surge with roughly 23,000 new cases reported daily. According to the Bloomberg COVID-19 tracker, more than 125 million vaccine doses have been administered in the country, providing coverage for 49.3 percent of the population. 

The incident threatens to damage confidence in the Moderna vaccine. The company has administered more than 200 million doses to more than 110 million people in 45 countries, rolling its vaccine out with surprising efficiency considering it was a relatively unknown company before the pandemic.