After several people had apparent allergic reactions at one California clinic, state health officials on Sunday told providers across the state to pause administering doses from one COVID-19 vaccine lot that arrived from Moderna.
The move, made “out of an extreme abundance of caution,” means that 330,000 doses distributed to 287 providers across the state can’t be used amid an already slow vaccine rollout.
“A higher-than-usual number of possible allergic reactions were reported with a specific lot of Moderna vaccine administered at one community vaccination clinic,” California State Epidemiologist Dr. Erica Pan said.
Officials said fewer than 10 people needed medical attention over the span of 24 hours, but didn’t clarify what their allergic reactions were.
“All appeared to be experiencing a possible severe allergic reaction during the standard observation period – a type of adverse event that the CDC reports some people have experienced when receiving a COVID-19 vaccine,” state health officials said in a news release.
The reactions are under investigation.
Meanwhile, providers were told to use doses from other available vaccine inventory until the investigation is complete. The pause applies only to one lot that came from Moderna, and not all the vaccine doses from the company.
The 330,000 doses of the affected lot arrived in California between Jan. 5 and 12 and were distributed across the state.
Health officials reminded residents that risk of a serious adverse reaction to the COVID-19 vaccine is very small, and the expected rate of anaphylaxis is about 1 in 100,000.
“The state has not been notified of any other cluster or individual events related to this lot,” officials said.
The clinic that had the allergic reactions switched to another lot of Moderna vaccine after closing for a few hours, according to the state.
The manufacturer, Centers for Disease Control and Prevention, and U.S. Food and Drug Administration are reviewing the lot and related medical information.
In a recommendation letter sent to providers Sunday, the state health department said it recognizes the extremely limited supply of vaccine, but added that there were no immediate replacement doses available during the pause.