Photo/Illutration A health care worker prepares a dose of Moderna's COVID-19 vaccine in Chiba in June. (Ryo Kato)

The contaminants found in Moderna COVID-19 vaccines distributed in Okinawa Prefecture are likely bits of rubber accidentally mixed in during the preparation process for the injection.

The health ministry is urging staffers involved in inoculation programs to be extra careful to prevent vial “coring,” which occurs when a needle is improperly inserted into the rubber stopper of a vial and shaves off some of the stopper.

The health ministry on Aug. 29 said the Okinawa vial mishap is unlikely to cause any harmful health effects and that inoculations should proceed as scheduled.

The Okinawa prefectural government had reported the day before that some of its Moderna vaccines may have been contaminated.

Small, black foreign substances were detected in a vial that was unsealed earlier that day, as well as in two loaded syringes, according to officials.

In another case, a pink-colored substance was found in a syringe, officials said.

The lot number for these vaccines was 3005293, according to prefectural officials.

Doses of vaccine from the same lot have been administered since Aug. 27.

Staff checked for possible contamination and administered the vaccine to 900 or so people in two days, officials said.

There have not been any reports of adverse effects to anyone’s health so far, officials said.

The health ministry said the black substances are most likely fragments of a rubber stopper that fell into the vial when staffers were preparing inoculations.

In these cases, no foreign substances were found in the vials before a needle was inserted through the rubber stopper, the ministry said.

The ministry said this kind of substance is less likely to harm someone's health because the rubber stopper is sanitized, and the materials are hypoallergenic and unlikely to clog blood vessels because the vaccine is delivered through an intramuscular injection.

Officials explained that when a needle is inserted into a vaccine vial at an angle, a portion of the rubber stopper can sometimes get sheared off, a phenomenon known as vial coring.

The ministry is now urging those administering vaccines to insert the needle into the vial vertically to prevent coring.

Conversely, the pink-colored substance that was detected cannot penetrate the needle because of its large size, the ministry said.

That substance was most likely mixed into the syringe barrel from the beginning, the ministry said.

The manufacturer of the syringe is expected to investigate into the composition of the substance and explain what caused it.

20210830-moderna-G-L
The Asahi Shimbun

TAINTED JABS REPORTED IN GUNMA

Gunma’s prefectural government on Aug. 29 also reported tainted Moderna vaccines.

Pharmaceutical technicians working at Toumou Vaccination Center in Ota discovered black specks floating inside a vial when transferring the vaccine from the vial to a syringe. 

Vaccines from the same lot number were administered to a total of 4,575 people from Aug. 27 to 29 at the center, Gunma officials said.

Gunma officials did not disclose the vaccine’s lot number.

But it is a different lot from the three that the health ministry has already recalled.

The lot number is also different from the one where the tainted vaccines were discovered in Okinawa Prefecture.

The center temporarily stopped taking new appointments but has resumed inoculations using vaccines from a different lot.

Nurses and pharmaceutical technicians at the site have checked every vial to ensure they did not contain foreign substances.

There have not been any reports of health safety concerns so far, officials said.

Related News