The state confirmed Monday that the “higher than usual” number of allergic reactions prompted California health officials Sunday to suspend the use of one group of Modern vaccines at a mass vaccination clinic in Petco Park in San Diego.
The California Department of Public Health on Sunday issued a statement recommending that health care providers stop stopping vaccines from the group, or lot, that arrived in California between Jan. 5 and Jan. 12. More than 330,000 doses from this group have been sent to 287 providers across the state.
It is unclear what other local vaccines have been received from this group, how many doses have been administered, and how the suspension of use of this group will affect the vaccinations across the country. No other groups of allergic reactions have been reported from other sites that have used vaccines of the same fate, the state said Sunday.
Some health care providers in Alameda County have received doses from this group, and public health officials are interrupting the administration of the doses, nationwide said Monday. No providers reported unusual reactions to public health officials, the country said.
Less than ten allergic reactions have been reported at Petco Park, which opened a drive-through mass vaccination center last week. All cases occurred within 24 hours and required medical attention.
The state did not immediately provide further details on the case. Last week, a public health official in San Diego County said that six health workers who were vaccinated in Petco Park apparently had allergic reactions, according to the LA Times.
“The number, put together, was slightly higher than expected for the period,” said Dr. Eric McDonald, director of epidemiology in San Diego County, said. He said the group had been swapped “in the event that” the reactions were linked, the Times reported.
The allergic reactions occurred within the observation period required after receipt of the vaccine. Due to early reports from a small number of people experiencing severe allergic reactions, regulators recommend that people receiving the vaccine be observed for 30 minutes thereafter.
Moderna said Monday he is working with the state health department to investigate the reported reactions. The company said it was not aware of similar side effects from other vaccination sites that administered doses from the same group.
“Moderna acknowledges that they received a report from the California Department of Public Health that a number of individuals were treated at one vaccination center for possible allergic reactions after vaccination from one of Moderna’s COVID-19 vaccines,” a Modern spokeswoman said in a written statement Monday. “The company is fully cooperating with CDPH in investigating these reported adverse events.”
The U.S. Centers for Disease Control and Prevention and the Food and Drug Administration are also reviewing the group.
The state said the risk of a serious adverse reaction is very small. It is unclear how many cases of severe allergic reaction occurred in humans after receiving the Moderna vaccine.
For a similar vaccine, manufactured by Pfizer, the risk is less than 1 in 100,000. According to the CDC, there were 175 cases of possible severe allergic reactions identified from nearly 1.9 million doses administered on December 23 in the United States.
Catherine Ho is a staff writer for the San Francisco Chronicle. Email: [email protected] Twitter: Cat_Ho