On Sunday, Dr. Erica S. Pan, the state epidemiologist, urged that providers stop using one lot of the Moderna vaccine because some people needed medical treatment for possible severe allergic reactions after receiving it.
Because the vaccine is new, people who administer it monitor recipients for 15 minutes after they get a shot. At Petco Park in San Diego, six people at a massive drive-thru clinic needed medical attention in a short period of time. No other similar clusters were found, Pan said.
“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” pending completion of an investigation by state officials, Moderna, the U.S. Centers for Disease Control and Prevention and the federal Food and Drug Administration, Pan said in a statement.
More than 330,000 doses from the lot, 41L20A, arrived in California between Jan. 5 and Jan. 12 and were distributed to 287 providers, she said. The doses represent about 10% of the state's total.
In Northern California, Stanislaus County health officials responded to the recommendation by announcing they wouldn’t be holding vaccination clinics until further notice.
Counties across the state are pushing to get more doses faster — but some say the setback may further delay vaccinations this week.
State officials emphasize that the risk of a serious adverse reaction to the Moderna formula is very small: 1 out of 100,000 people.
—Molly Peterson, KQED, and Robert Jablon, Associated Press