On Tuesday, August 31, Japan announced more batches of Moderna COVID-19 vaccines were suspended over the detection of contaminants, making it the fourth time in a week for such incidents.
According to Reuters, the new Moderna vial incident was reported by a pharmacist in Kanagawa, a coastal prefecture residing south of Tokyo, after an initial check for foreign substances detected several black fragments.
Kanagawa prefecture said Takeda Pharmaceutical, the company in charge of vaccine distribution in the country, had retrieved the vial containing the suspected contaminate.
Around 3,790 people in the region had been administered the shots from the same batch.
On Wednesday, Sept. 1, Takeda said on its website that rubber stoppers might break off and find their way into the vaccine formulation on rare instances during production, according to Reuters.
On the same day, Japan’s health ministry repeated a similar explanation for the newly tainted vaccines in Kanagawa, adding that the affected lot sent to the prefecture came from different sources than the other contaminated vials.
The country first halted batches of Moderna vaccines last Friday, August 31, following reports of foreign particles found in some of the doses, with an estimate of nearly 1.63 million shots being affected.
The cause was suspected to be related to the manufacturing company in Spain, which prepared the Moderna shots exclusively for Japan.
Then on the following day, two fatalities were reported. The male patients in their 30s were said to have received the doses in the suspected vaccine batches. An investigation had been launched, but officials were not admitting to any link between the vaccines and the patients’ cause of death.
As of Sunday, more vials in two country regions were suspended, with reports saying black and pink particles were found.
According to Moderna, no safety or efficacy issues have been detected as a result of the problem. There have been no reports of similar Moderna incidents in other nations.
Japan is still in a battle with the Delta variant-driven outburst, Reuters noted, with last month having new infection rates per day increasing to 25,000 cases, an all-time high ever since the virus infected the country.
Only 45.4 percent of the population has been fully vaccinated, far behind other developed countries’ immunization rates.