LOS ANGELES (KRON/AP) — California’s state epidemiologist is urging a halt to more than 300,000 coronavirus vaccinations using a Moderna vaccine version because some people received medical treatment for possible severe allergic reactions.

Dr. Erica S. Pan on Sunday recommended providers stop using lot 41L20A of the Moderna vaccine pending completion of an investigation by state officials, Moderna, the U.S. Centers for Disease Control and the federal Food and Drug Administration.

“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,” Pan said in a statement.

She said more than 330,000 doses from the lot arrived in California between Jan. 5 and Jan. 12 and were distributed to 287 providers.

Fewer than 10 people, who all received the vaccine at the same community site, needed medical attention over a 24-hour period, Pan said. No other similar clusters were found.

“It’s a single lot vaccine that’s a lot of doses, it’s more than 300-thousand doses,” Dr. George Rutherford said.  

Dr. George Rutherford with UCSF says the problem triggering the reaction, a component found in everyday things. 

The problem he says, many people have no idea they’re allergic, until after they receive the vaccine. 

“There’s a component of the vaccine called polyethyleneglycol or PEG which is a component which is found in things like, used in cosmetics and a preservative in foods. So we get exposed to it just in everyday life. If you know you’re allergic to it, you shouldn’t get vaccinated,” Rutherford said. 

Doses from the same lot were distributed here in the Bay Area:

Alameda County

Alameda County tweeted that they “have not received or administered vaccine from this Lot, but some local providers did receive doses from it.”

Santa Clara County

Santa Clara County released a statement on the public health website “recommending providers pause the administration of lot 41L20A of the Moderna COVID-19 vaccine due to possible allergic reactions that are under investigation.” 

The county says 21,800 doses from this lot were distributed, however, the county has no knowledge of the vaccines actually being administered to residents at this time.

San Francisco

In San Francisco, officials said its Department of Public health had not yet received any reports of anyone experiencing negative impacts from doses in Lot 041L20A.

Health officials also say they have not yet received reports of anyone experiencing negative impacts from the doses in that specific lot.

Rutherford says, if you have other allergies, you should be ok to receive the vaccine. 

“If you have other allergies like peanuts or something like that there’s no reason not to get vaccinated, just tell them if you have had an anaphylactic reaction, severe reaction, and just tell them and they’ll watch you for another 15 minutes,” Rutherford said. 

However, six San Diego health care workers had allergic reactions to vaccines they received at a mass vaccination center on Jan. 14. The site was temporarily closed and is now using other vaccines, KTGV-TV reported.

Moderna in a statement said the company “is unaware of comparable adverse events from other vaccination centers which may have administered vaccines from the same lot.”

The CDC has said COVID-19 vaccines can cause side effects for a few days that include fever, chills, headache, swelling or tiredness, “which are normal signs that your body is building protection.”

However, severe reactions are extremely rare. Pan said in a vaccine similar to Moderna, the rate of anaphylaxis — in which an immune system reaction can block breathing and cause blood pressure to drop — was about 1 in 100,000.

The announcement came as California counties continue to plead for more COVID-19 vaccine as the state tries to reduce its rate of infection, which has led to record numbers of hospitalizations and deaths.

California, with a population of 40 million, has received about 3.5 million vaccine doses and has only administered about a third of them, according to the CDC.

So far. the state has vaccinated just 2,468 people per 100,000 residents, a rate that falls well below the national average, according to the federal data.