The news that a foreign substance — thought to be metal fragments — has been discovered in dozens of vials of Moderna Inc.’s COVID-19 vaccine distributed in Japan could shake people’s faith in the vaccine, but manufacturers and experts have downplayed safety risks and their impact on human health.
Complicating the matter further, the weekend brought news of more tainted vaccines in Okinawa and Gunma prefectures and the deaths of two men in their 30s three days after they received shots from affected batches. Here is a rundown of the current situation.
What has been the impact of the discovery of the foreign substances?
The government on Thursday reported that the foreign substance had been discovered in 39 unused vials, all of which had the lot number 3004667, at eight workplace and large-scale inoculation sites in five prefectures — Aichi, Ibaraki, Gifu, Saitama and Tokyo — with the first discovery having come on Aug. 16.
The government has decided to halt the use of vials belonging to that lot number (about 57,000 vials, equivalent to 570,000 shots), as well as those with the lot numbers 3004734 (about 52,000 vials, or 520,000 shots) and 3004956 (about 54,000 vials, or 540,000 shots) despite no reports of contamination, as they were produced around the same time and on the same production line in Spain. The vials with the three lot numbers had been distributed to nearly 900 vaccination centers across Japan and more than 500,000 of the affected shots had already been administered.
There had been no reports of ill health from the affected batches until Saturday, when Moderna and Takeda Pharmaceutical Co., the distributor of the U.S. firm’s COVID-19 vaccine in Japan, received reports of the deaths of two men, age 30 and 38, who had no history of allergies or other underlying conditions. They were confirmed dead three days after they received a second Moderna dose, both from the lot number 3004734.
Takeda and Moderna said in a joint statement Saturday that they have received no reports of particulate matter in the lot used in the two people’s shots and added that they have no evidence that their deaths were caused by the Moderna vaccine. The government has pledged to conduct a swift investigation involving external experts to see if there is a causal relationship between their deaths and the inoculations.
The vials in question were made by Laboratorios Farmaceuticos Rovi, which has been handling the final step in the manufacturing process for Moderna vials that use vaccine ingredients produced in Switzerland and are destined for non-U.S. markets. The Spanish pharmaceutical firm has said that the one product lot in which the foreign substance has been detected was distributed exclusively in Japan.
What’s the impact on health?
Infectious disease experts say the risk that a contaminated vial would be administered is low, as the standard protocol is to check for any abnormalities in vials and syringes before use. But even if the foreign substance went undetected and were administered inside the muscle, the chance of a significant health problem occurring is deemed to be low, said Takeshi Terashima, an infectious disease expert and the general manager of respiratory medicine at Tokyo Dental College Ichikawa General Hospital.
“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 intramusclar injection through a 0.25 millimeter needle would be extremely unlikely,” Terashima said on a TBS News program Friday.
Masayuki Miyasaka, professor emeritus of immunology at Osaka University, also said on his Facebook page, “If it’s a minute piece of metal, once injected inside the muscle it will be approached and eaten by phagocytes, so it will not circulate in the whole body, and there is a near zero chance of it causing substantial health damage.”
Have there been any other reports of contaminated Moderna shots?
Okinawa Prefecture halted administering the Moderna vaccine at a mass vaccination center in Naha on Saturday and Sunday after four instances of black dot-like particulate matter were confirmed inside loaded syringes and a punctured vial, though the usual pre-usage examination of the vials did not confirm any foreign materials inside. A total of five foreign substances have been identified related to lot number 3005293, including a pink substance that was detected inside a loaded syringe in Okinawa on Saturday.
The health ministry has said there are no issues with the safety and efficacy of the vials with that lot number, and Okinawa resumed vaccinations at the center on Monday.
An investigation by Takeda showed that there’s a high possibility that the black foreign material was rubber that was shaved off when the syringes pierced through the rubber stoppers of the vials. As for the pink substance, that material is too big to be introduced by a syringe into a vial, so it may have already been inside, the ministry said.
A foreign substance was also observed at a mass vaccination center in Ota, Gunma Prefecture, with what looked like a black dot seen inside a vial on Sunday before it was used. The vial’s lot number was different to the three suspended by the government and the one halted by Okinawa. Vials with the same lot number were used to vaccinate 4,575 people over three days through Sunday, but so far there have been no reports of ill health, the prefecture said in a statement.
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