Santa Clara County distributed 21,800 vaccine doses from batch that sickened others

Frozen vials of the Covid-19 vaccine are defrosted for use in San Francisco. AP photo.

State epidemiologist Dr. Erica S. Pan 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.

Some of those vaccine doses had already been distributed by Santa Clara County.

Pan recommended Sunday (Jan. 17) that 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.

Santa Clara County is “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.

People in Alameda and San Francisco counties may have received some of the doses too.

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

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.

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.

Moderna said it “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 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. — By the Associated Press