The “higher-than-normal” number of allergic reactions that prompted California health officials on Sunday to pause the use of a modern vaccine batch occurred at a mass vaccination clinic in Petco Park in San Diego, confirmed the on Monday.
The California Department of Public Health issued a statement on Sunday recommending that health professionals stop using vaccines from the batch, or batch, which arrived in California between January 5 and 12. More than 330,000 doses of this batch were shipped to 287 suppliers across the state.
It is not clear which other locations received vaccines from that batch, how many doses were administered and how the suspension of the use of that batch will affect vaccinations across the state. No other set of allergic reactions has been reported on other sites that used vaccines from the same batch, the state said on Sunday.
Some health care providers in Alameda County have received doses of this batch, and public health officials are ensuring that administration of these doses is paused, the county said Monday. No provider reported unusual reactions to public health officials, the county said.
There have been less than 10 allergic reactions reported at Petco Park, which last week opened a mass drive-through vaccination site. All cases occurred within 24 hours and required medical attention.
The state did not immediately provide further details about the case. But last week, a San Diego County public health official said that six health workers who were vaccinated at Petco Park had apparent allergic reactions, according to the LA Times.
“That number, grouped together, was slightly higher than expected for the time period,” said Dr. Eric McDonald, director of epidemiology for San Diego County. He said the batch was changed “in the event of possible reactions” being connected, the Times reported.
Allergic reactions appeared to occur within the required observation period after administration of the vaccine. Because of the first reports of a small number of people with severe allergic reactions, regulators recommend that people who get the vaccine be observed for 30 minutes later.
Moderna said on Monday that it is cooperating with the state health department to investigate the reported reactions. The company said it is not aware of comparable adverse events from other vaccination sites that may have administered doses from the same batch.
“Moderna acknowledges having received a report from the California Department of Public Health that several individuals at a vaccination center were treated for possible allergic reactions after vaccination of a batch of Moderna’s COVID-19 vaccine,” said a spokesman. da Moderna in a statement written on Monday. “The company is fully cooperating with CDPH in investigating these reported adverse events.”
The United States Centers for Disease Control and Prevention and the Food and Drug Administration are also analyzing the batch.
The state said the risk of a serious adverse reaction is very small. It is not clear how many cases of severe allergic reaction occurred in people after receiving the Modern vaccine.
For a similar vaccine, made by Pfizer, the risk is less than 1 in 100,000. There have been 175 cases of possible serious allergic reactions identified in nearly 1.9 million doses administered in the United States on December 23, according to the CDC.
Catherine Ho is a writer for the San Francisco Chronicle. Email: [email protected] Twitter: Cat_Ho