Two cases of a coronavirus variant first found in South Africa that reduce the effectiveness of some vaccines have been identified in the Bay Area in the provinces of Alameda and Santa Clara, Govin Newsom said on Wednesday.
These are the first two cases of this variant, called B.1.351, found in California. They were identified by scientists at the Stanford Clinical Virology Laboratory on Tuesday night and reported to the state on Wednesday morning.
Variants that are more contagious or reduce the effectiveness of the vaccine pose a threat to the state’s ability to control the pandemic and end it quickly, public health officials said. More than 150 cases of a variant first identified in the United Kingdom that are known to be more contagious have been found in California, including the provinces of Alameda and San Mateo.
A few more closely related variants identified in California have spread rapidly in the Bay and Southern California. Scientists believe that these variants respond to vaccines, but they are now conducting tests to determine if it reduces their effectiveness. They also study whether the variants are more contagious.
The variant from South Africa is considered particularly worrying because studies have found that it can partially evade the body’s immune response, either through a vaccine or previous infection with the coronavirus. So far, it appears that the vaccines prevent serious diseases and deaths due to the variant.
‘The British variant, it’s still susceptible to vaccines and it’s going to spread anyway. But let’s get this one in the box again, ‘said dr. George Rutherford, an expert in infectious diseases at UCSF, said.
According to the Centers for Disease Control & Prevention, three cases of South Africa were identified in three states on Tuesday. The number does not include the new California business.
“These variants are here,” said dr. Nicholas Moss, chief medical officer of Alameda County, said during a press conference on Wednesday. “We have to prepare and plan accordingly.” Because relatively few coronavirus cases were genomically sorted, he said, “We have only a very limited picture of their distribution locally.”
The two vaccines currently available in the United States, made by Pfizer and Moderna, provide some protection against B.1.351, but perhaps less than the initial virus from China for which it was designed.
The Moderna vaccine elicited an immune response that was six times lower compared to the South African variant compared to earlier variants, the company said in late January after conducting a small study. But even this lower level of immune response, or neutralizing antibodies, is likely enough to protect against COVID-19, the company said.
Nevertheless, Moderna is testing a booster vaccine to see if it can provide more immunity.
Similarly, the Pfizer vaccine also caused a slightly lower level of neutralizing antibodies against the variant, but it should still be sufficient to protect against COVID-19, according to studies by Pfizer and the University of Texas Medical Branch. The difference is likely that it will not lead to a significant decrease in the effectiveness of the vaccine, Pfizer said.
South Africa has recently stopped using a vaccine made by AstraZeneca due to its reduced efficacy. That vaccine has not yet been approved for use in the United States. Scientists in South Africa have also said that people previously infected with other coronavirus variants appear to be susceptible to re-infection with the new one.
Moss from Alameda County has expressed optimism about vaccines. But in the meantime, he said, “We need to stick to the things we know work for the time being. That means making face masks, distance and limited gatherings.”
“The most important thing with variants is to limit only the amount of COVID that is there,” he added.
San Francisco Chronicle staff writers Aidin Vaziri and Catherine Ho contributed to this report.
Erin Allday is a staff writer for the San Francisco Chronicle. Email: [email protected] Twitter: @erinallday