Yet another contaminated Moderna Covid-19 vaccine has been reported in Japan - the fourth in less than a week, according to Reuters, which reports that 'several black particles' were found in a Moderna vaccine vial in Kanagawa prefecture.
The remainder of the lot has been placed on hold.
Last week Japan suspended the use of 1.63 million Moderna doses after being notified of a contaminant which 'could be metal' and reacts to magnets.
Moderna and Spanish pharma company Rovi, which bottles the vaccines, says the cause could be a manufacturing issue.
Kanagawa prefecture said the vaccine's domestic distributor, Takeda Pharmaceutical Co Ltd, had collected the vial with the suspected contaminant and that about 3,790 people had already received shots from the same lot.
More Moderna shots were temporarily halted in two other regions this week. In some cases, foreign substances have been found in unused vials, whereas others appear to be caused when bits of the vials' rubber stopper break off when needles are incorrectly inserted. -Reuters
On Wednesday, Japan's health ministry said that the vial sent to Kanagawa was from a different lot than the previous contamination reports, but has said that 'rubber stopper material' appears to have gone into it during the manufacturing process (which would contradict last week's report that the material 'reacts to magnets').
Medical staff are being encouraged to perform visual inspections of vials for foreign materials or discoloration before use.