The worrisome South African strain of the COVID-19 virus, which appears to be more contagious and more resistant to some vaccines, has once again surfaced in Santa Clara County.
Unlike the first case, detected in February, this new case is not travel-related and is believed to have resulted from community transmission. Health officials didn’t provide any more details.
“This latest case confirms that we do have community transmission, and reminds us to not let down our guard in the middle of this pandemic,” Dr. Sara Cody, Health Officer and Director of Public Health for the County of Santa Clara, said in a statement.
“Considering the national trends, we have been operating under the assumption that these variants were circulating at some level in our communities,” she said.
It is the fourth case reported in California. In February, officials announced the detection of a case in Santa Clara County in an adult who had traveled internationally, but who quarantined after showing symptoms. Another February case was reported in Alameda County. Officials have not reported the source of the fourth case.
The South African variant is able to elude the AstraZenca vaccine, although two other vaccines — made by Moderna and Johnson & Johnson — offer some protection.
But despite its danger, this South African variant has not gained much of a foothold in the United States. First detected in the U.S. in January in South Carolina, only 142 cases in 25 states have been found.
In contrast, two other strains – one that emerged in California, the other imported from the United Kingdom – are causing widespread concern.
One, now being called the West Coast strain, is estimated to be 20% more transmissible than the original circulating variant. Another, imported from the United Kingdom, is thought to be as much as 50% more transmissible. The South African variant is also believed to be around 50% more contagious.
There have been 6,628 California cases of the West Coast strain. As of mid-February, it accounted for more than half of all sequenced samples in California, more than one-third of Nevada samples and one-quarter of Arizona samples.
This week the CDC declared the homegrown strain a “variant of concern,” citing its ease of contagion and ability to blunt the body’s immune response.
There have been 375 California cases of the variant from the United Kingdom. But it is surging elsewhere. It has been found in all 50 states and the District of Columbia and is on track to become the nation’s dominant variant.
In Santa Clara County, 15 cases have been linked to this U.K. variant.
Last Saturday, California reported its first case of a dangerous variant from Brazil. It is not known how the patient, a San Bernardino County man, acquired his infection. This strain is unique from another Brazilian variant, which has been found in the Bay Area but is considered less dangerous.
Health officials caution that the true level of community spread tied to these variants is unknown, since current genomic sequencing capabilities only allow a fraction of positive cases to be sequenced.
“Even with these variants circulating in our community, the best tools to protect ourselves and our loved ones remain familiar to us and are available now,” said Dr. George Han, deputy health officer for the County of Santa Clara.
“Wear your masks, keep your distance from others, avoid gatherings, especially indoors,” he said. “And get vaccinated when it’s your turn.”