On the same day, however, officials in both Santa Clara and San Mateo counties announced the pause in their administration of the one-shot Johnson & Johnson vaccine due to the discovery of a rare side effect among patients elsewhere in the nation.
The increased supply, which comes after weeks of shortages, is coming directly to the county's health system from the federal government under a program operated by the federal Health Resources & Services Administration. As a result of the expanded vaccine supply, the county opened vaccine eligibility to all residents and workers ages 16 or older on Tuesday, two days earlier than the April 15 date designated by the state.
"This is really a game changer," Santa Clara County Supervisor Otto Lee said Tuesday of the boost in doses. "This is close to four to five times the vaccines we have been getting,"
Health officials breathed a collective sigh of relief at Tuesday's press conference after learning about the large allocation from the federal government earlier in the day.
"We're thrilled to provide expanded access to these highly effective vaccines, especially for those most impacted by COVID-19," said Dr. Marty Fenstersheib, the county's testing and vaccine officer. "We will be able to offer vaccination to those at greatest risk and ensure broad coverage for our entire community."
The county received the first shipments of additional vaccines from the U.S. government on Tuesday morning and additional supplies are expected to arrive next week.
Dr. Jennifer Tong, assistant chief medical officer for the Santa Clara County Valley Medical Center, said they expect heavy traffic on the county's vaccine signup website — sccfreevax.org — in the next few days. People should expect delays but should continue to return to the site to book an appointment as more will keep opening up.
Anyone without access to the internet can book a vaccine appointment by calling the county at 211 or 408-970-2000.
The increase in vaccine supply comes on the heels of announcements by both Santa Clara and San Mateo counties that they would halt administration of the single-dose Johnson & Johnson vaccine, which the U.S. Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) caution may have caused a severe type of blood clot in six people.
Although rare — they are the only known cases out of about 7 million doses administered nationwide — CDC and FDA officials and the local authorities said they were halting the shots out of an abundance of caution.
"In these cases, a type of blood clot called cerebral venous sinus thrombosis was seen in combination with low levels of blood platelets (thrombocytopenia). All six cases occurred among women between the ages of 18 and 48, and symptoms occurred 6 to 13 days after vaccination. Treatment of this specific type of blood clot is different from the treatment that might typically be administered. Usually, an anticoagulant drug called heparin is used to treat blood clots. In this setting, administration of heparin may be dangerous, and alternative treatments need to be given," Dr. Anne Schuchat, the CDC's principal deputy director, and Peter Marks, director of the FDA Center for Biologics Evaluation and Research, said in a joint statement on Tuesday.
Santa Clara County health officials said the county should be able to cover all scheduled Johnson & Johnson appointments with the Pfizer-BioNTech or Moderna vaccines. County officials have also advised their vaccinating partners to pause administration of the Johnson & Johnson vaccine until further direction from the CDC, FDA and California Department of Public Health.
Fenstersheib said on Tuesday afternoon that 62,000 people have received the J&J vaccine in Santa Clara County. He urged people to understand that the complications are "extremely, extremely rare." Symptoms include a severe headache, abdominal or leg pain or shortness of breath. Anyone who has these symptoms should contact their health care provider or seek medical help, he said.
One of the six people who suffered a blood clot after getting the one-shot vaccine died, but no cases of complications from the J&J vaccine have been found in California, he said.
People who received the J&J vaccine more than a month ago have a very low risk of developing the symptoms, he added.
Tong said the blood clotting can occur in people who have not been given the Johnson & Johnson shot, so it is not yet known if the vaccine actually caused the clotting.
Dr. Anand Chabra, San Mateo County's COVID-19 vaccination branch chief, said in a Tuesday statement that the county has directed its partnering clinics and hospitals to suspend its administration until the vaccine is officially cleared by the CDC and FDA.
In San Mateo County, 22,306 shots of the J&J vaccine have been administered out of the 564,367 total vaccinations by the county Health Department, health care providers and hospitals, pharmacies, community clinics and other partners.
"This represents 3.952% of total vaccines administered in San Mateo County, the others being the Pfizer and Moderna vaccines," he said.
"San Mateo County Health received 500 Janssen (J&J) doses this week, which will be held pending further state and federal guidance," he said.
"The county does have some targeted events planned with J&J this week, but we have been able to supply those events with available Pfizer and Moderna doses so that those events can still take place at the same number of doses as planned," he said.
The CDC planned to hold a meeting of the Advisory Committee on Immunization Practices on Wednesday, April 14, to further review the six cases and to assess their potential significance, the federal authorities said.
Health care providers are asked to report adverse events to the Vaccine Adverse Event Reporting System.