TOKYO (Reuters) – Japan’s health minister explained on Tuesday it was remarkably likely that overseas issue uncovered in Moderna Inc COVID-19 vaccines in the southern prefecture of Okinawa were caused when needles were being caught into the vials.

Some Moderna shots were quickly halted in Okinawa on Sunday right after foreign products were identified in vials and syringes. The health and fitness ministry mentioned later needles might have been improperly inserted into vials, breaking off bits of the rubber stopper.

“Whatsoever the cause (for the overseas matter) we have read that there is no basic safety or other difficulties,” wellness minister Norihisa Tamura explained to reporters, introducing that it was not unusual for international materials to enter a vial with other vaccines.

“We will continue to obtain data and report back again,” he included.

Japan is facing its most significant wave of COVID-19 infections so far all through the pandemic, driven by the extremely transmissable Delta variant.

A race to strengthen inoculations has been hampered by delays in imported vaccines and the discovery of the contaminants in some Moderna doses that prompted the suspension of a few batches last week.

Taro Kono, the minister in charge of the inoculation marketing campaign, reported on Tuesday he preferred to pace up shipments of vaccines to municipalities that had been pressured to set a halt reservations due to shortages.

The federal government is looking at when and how to give out booster photographs that may be desired to maintain immunity in opposition to the virus but is concentrating for now on finishing the to start with two photographs for the community, Kono advised reporters.

(This tale refiles to correct “the place” to “had been” in initial paragraph)

(Reporting by Mari Saito and Rocky Swift in Tokyo Modifying by Richard Pullin)