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Jan. 18, 2021 -- California paused giving more than 300,000 Moderna vaccine doses after several people received medical treatment for potential severe allergic reactions, according to The Associated Press.

The specific lot of the Moderna vaccine — 41L20A — is being investigated by state officials, Moderna, the CDC and the FDA.

“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,” Erica S. Pan, MD, California’s state epidemiologist, said in a statement.

About 330,000 doses from the lot were distributed to 287 health care providers across the state between Jan. 5-12, Pan said. Fewer than 10 people have required medical attention during a 24-hour period after receiving the vaccine at one community site, she added. All appear to be experiencing a possible severe allergic reaction. The state hasn’t been notified of other clusters or individual events related to the lot of Moderna vaccines, she said.

In San Diego, six health care workers had allergic reactions to vaccines at the Petco Park vaccination center on Jan. 14, according to KTGV-TV. The site was closed after the reports but is now open again and using other vaccine batches.

COVID-19 vaccines can cause side effects such as fever, chills, headache or fatigue, which is a normal reaction and a sign that the body is building immunity. Severe reactions are rare, and anaphylaxis occurs in about 1 in 100,000 people.

Officials will provide an update this week as more information becomes available, Pan said.

Show Sources

Associated Press: “California urges stop to 300K vaccines after some fall ill.”

California Department of Public Health, “California State Epidemiologist Statement Recommending Providers Pause Administration of Single Lot of Moderna COVID-19 Vaccine.”

KTGV-TV: “Specific lot of Moderna COVID-19 vaccine put on pause in California after allergic reactions.”

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