Moderna investigates reports of allergic reactions to its coronavirus vaccine

Modern (NASDAQ: ARNM) said on Tuesday he was investigating a few cases in which patients appeared to have allergic reactions to his coronavirus vaccine. All of the reported incidents, in which people have experienced reactions after their first injection of mRNA-1273, have occurred at a vaccination clinic in San Diego. (The vaccine is given in two doses, with injections given 21 days apart.)

The California Department of Health did not specify the exact number of people in the cluster who experienced these reactions, but California state epidemiologist Dr Erica S. Pan said there had less than 10 people in a 24 hour period.

In each of these cases, the vaccine came from a single lot – No. 41L20A, which included over 1.27 million doses that were distributed to approximately 1,700 vaccination sites in 37 states. Over 330,000 of them have gone to California. It is not known exactly how many of them have already been used. So far, no similar group of allergic reactions have been reported.

Following reports regarding the San Diego cluster on Sunday, Dr Pan – in a decision she said she made “[o]with extreme caution ”- issued a formal recommendation asking healthcare providers to immediately suspend the use of the vaccines from the batch in question. Pan promised that she would provide an update as her department learned more about the incidents.

As for Moderna, the company said it was working with federal health officials to investigate possible causes for the reactions in California. He added that he was not aware of any clusters of similar incidents elsewhere.

So far, mRNA-1273 remains one of only two coronavirus vaccines to have received emergency use clearance from the Food and Drug Administration. Like the other, Pfizer and BioNTechBNT162b2, it is distributed nationwide and the available supply is administered to populations most exposed to COVID-19.

The vaccine rollout process has been slower than expected, however, and new President Joe Biden has pledged to step up the pace in the weeks and months to come.