The Los Angeles Times is reporting that in a study conducted by researchers at the University of California, San Francisco (UCSF), it was found that the variant, which the virologists call B.1.427/B.1.429, might not only be more contagious but may also cause more severe disease.
The cluster of mutations that characterizes the homegrown strain should mark it as a “variant of concern” on par with those from the United Kingdom, South Africa, and Brazil, according to Science Magazine.
“This variant is concerning because our data shows that it is more contagious, more likely to be associated with severe illness, and at least partially resistant to neutralizing antibodies,” says senior author Charles Chiu, an infectious diseases physician and sequencing expert at UCSF.
Dr. Chiu notes that the California variant wasn’t seen in blood samples in September, but by the end of January, accounted for nearly 50 percent of illnesses, based on samples collected. The data suggest the new strain “should likely be designated a variant of concern warranting urgent follow-up investigation,” the authors write in their preprint, which has not been peer-reviewed and which they say is expected to be posted online soon.
Details of the variant
The California variant has a different pattern of mutations than the ones first seen in the United Kingdom and South Africa. The new variant, which comes in two forms labeled B.1.427 and B.1.429 that carry slightly differing mutations, accounted for 21.3 percent of these sequences overall, reports CNN.
B.1.427/B.1.429’s genome includes three mutations that affect the crucial spike protein, which the virus uses to sneak into human cells and convert them into factories for its own production. One of those three mutations, dubbed L452R, affects the so-called receptor binding domain, helping the virus attach more firmly to target cells.
In further studies of the medical records of 324 patients admitted to UCSF clinics or its medical center, the researchers found that compared with patients who had other viral strains, those carrying the new variant were 4.8 times more likely to be admitted to the ICU and more than 11 times more likely to die.
In lab studies, “B.1.429 also impacted the effectiveness of antibodies: It was four times less susceptible than the original coronavirus to neutralizing antibodies from the blood of people who recovered from COVID-19, and two times less susceptible to antibodies from the blood of people vaccinated with the Pfizer or Moderna vaccines.”
That diminished potency is “moderate but significant,” the researchers wrote.
Dr. Anthony Fauci, the nation’s top infectious diseases expert, raised a further concern in an interview with The Times. A “survival-of-the-fittest contest between the U.K. and California variants could accelerate the spread of the strain that’s best able to elude the effects of COVID-19 vaccines,” he said.