Moderna says possible allergic reactions to Covid-19 vaccine under investigation

Moderna Inc said on Tuesday it had received a report from California's health department that several people at a center in San Diego were treated for possible allergic reactions to its Covid-19 vaccine from a particular batch.

The company's comments come after California's top epidemiologist on Sunday issued a statement recommending providers pause vaccination from lot no. 41L20A due to possible allergic reactions that are under investigation.

"A higher-than-usual number of possible allergic reactions were reported with a specific lot of Moderna vaccine administered at one community vaccination clinic. Fewer than 10 individuals required medical attention over the span of 24 hours," the epidemiologist said in a statement.

The vaccine maker said it was unaware of comparable cases of adverse events from other vaccination centers which may have administered vaccines from the same lot or from other lots of its vaccine.

A total of 307,300 doses from the lot remain in storage, Moderna said, of the total 1,272,200 doses that were produced in the batch.

Moderna said it was working closely with US health regulators to understand the cases and whether pausing the use of the lot was warranted.

Nearly a million doses from the lot have already been distributed to about 1,700 vaccination sites in 37 states, Moderna said.