Tokyo, Aug 30 (EFE).- Japanese authorities said Monday they are still investigating the origin of impurities found in several Moderna Covid-19 vaccine vials manufactured in Spain, some of which apparently come from the caps of the bottles.

Japan blocked 1.63 million doses Thursday as a precautionary measure, after "foreign substances" were found in 39 vials (bottles containing 10 doses), according to the Health Ministry.

The doses, whose use was suspended, had been distributed for application in five Japanese prefectures (Ibaraki, Saitama, Tokyo, Gifu and Aichi), corresponding to three batches of the vaccines and about 500,000 had already been inoculated.

Subsequently, local authorities of two other prefectures, Okinawa and Gunma, temporarily stopped their use after impurities were found in vials from lots other than those blocked Thursday.

The Health Ministry "is making efforts to gather information on the details of these cases and on anomalies detected, and will study the possible causes in a committee of experts," Executive spokesman Katsunobu Kato said at a Monday press conference.

The government also announced Saturday it is investigating the death of two people who were vaccinated with one of the three Moderna batches before being withdrawn, to try to clarify whether they are connected to the inoculation.

At the moment "it is unknown if there is a relationship" between deaths and vaccination, Kato said Monday, adding that the deaths were announced "to provide transparency" to the vaccine monitoring process.

Both Moderna and its distributor in Japan, Takeda, and the Spanish pharmaceutical company Rovi, which produces the American firm's vaccine for the European and Japanese markets, are investigating the origin of the problem and health risks.

In the case of the impurities detected in Okinawa, it is believed they would be remnants of the rubber stoppers of the vials that would have come off when the syringe needle was inserted improperly, according to the Health Ministry.

Takeda said the vials did not show irregularities before use, according to Japanese authorities, who said the detached fragments do not pose health risks as they are too large to pass through the needle.

The Health Ministry reissued a guide of recommendations to avoid a recurrence of this problem, which was also observed when administering vaccines from other manufacturers and in different places.

As for anomalies in Moderna's blocked vials, the US pharmaceutical company said it hopes to have the results early this week of an independent laboratory to which it sent samples. EFE

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