Moderna vaccine batch may be suspended after adverse events

State Epidemiologist Dr Erica Pan called for pausing administration of Moderna's coronavirus vaccine due to a high-than-usual number of severe allergic reactions.

Officials said that less than 10 individuals in over a 24-hour span needed medical attention but did not explain their allergic reactions.

After the reactions were reported, the community clinic closed for a few hours this weekend and then switched to using another lot of Moderna vaccine.

"Out of an extreme abundance of caution and also recognizing the extremely limited supply of vaccine, we are recommending that providers use other available vaccine inventory", the health official said. "We're going to pause as recommended until we hear more from the state, but without replacement doses, we're balancing one set of risks against another".

Between Jan. 5 and 12, the 330,000 doses of the affected lot arrived in California and were spread throughout the state.

The pause on the lot is in place until an investigated conducted by the CDC, FDA, Moderna, and state health officials is complete.

As the Chronicle reports, the allergic reactions were found at the mass-vaccination site at San Diego's Petco Park.

Investigation into the lot is led by the manufacturer, the Centers for Disease Control and Prevention and the Food and Drug Administration. The rate of anaphylaxis in the Moderna vaccine was expected to be about one in every 100,000, officials said.

The drive-thru facility immediately swapped out the batch of vaccines it was administering "in the possible event" there was a connection between the lot and the reaction, Dr. Eric McDonald said Wednesday. It was not clear which other locations received the affected doses.

California Governor Gavin Newsom has set a goal of inoculating 1 million more Californians by the end of this week with the first shot of the two-dose vaccine.