The mutated virus — known as L452R — was first detected in Denmark in March and has since been confirmed in more than a dozen states, including California in May. The discovery did not garner much attention at the time because all viruses change constantly as they replicate and adapt. But public health authorities deem some variants to be “of concern” if evidence suggests they might be more contagious or potentially deadlier.
California publicized the variant at a late Sunday news conference after researchers identified it in about 25 percent of samples collected between Dec. 14 and Jan. 3, a surge from 3.8 percent of samples collected in the three-week period leading up to Dec. 14.
“That is suggestive, and it’s a little worrisome,” Charles Chiu, a virologist at the University of California San Francisco said at the briefing. But Chiu stressed it was premature to conclude the variant is more infectious because scientists do not know if their sampling was representative, or whether the variant’s increase might be due to random chance, or even several superspreader events.
Officials stressed the importance of following public health guidelines to minimize all risk of spreading the variant as new cases in the hard-hit begin to plateau at more than 38,000, while deaths average more than 525 deaths daily.
“It’s too soon to know if this variant will spread more rapidly than others,” said Erica Pan, California’s state epidemiologist, “but it certainly reinforces the need for all Californians to wear masks and reduce mixing with people outside their immediate households to help slow the spread of the virus.”
Genetic sequencing of viruses is still limited in the United States, preventing health officials from having a real-time picture of all the strains of coronavirus spreading across the country and their prevalence.
California’s preliminary data is based on fewer than 400 samples that overwhelmingly came from Northern California. Southern California is the heaviest hit parts of the state with deaths in Los Angeles County reaching one every seven minutes and ICU beds and oxygen running out, although hospitalizations have begun to stabilize.
This rising variant in California is not the same as the highly contagious one first identified in the United Kingdom, known as B. 1.1.7, which could become the dominant strain in the United States by March, according to the Centers for Disease Control and Prevention. That strain has been identified in at least 12 states including California, and scientists do not believe it is deadlier or resistant to vaccines.
The L452R strain in California raised alarms because it is associated with several large outbreaks in Santa Clara County, including one at a hospital that infected at least 90 people and killed one. Officials at Kaiser Permanente San Jose Medical Center say a staff member wearing an inflatable Christmas tree costume to spread holiday cheer likely spread coronavirus-laden droplets instead.
Sara Cody, Santa Clara’s top public health official, described that episode as a “very unusual outbreak with a lot of illnesses and it seemed to spread quite fast.” The county is working with state health officials and the CDC to investigate what happened, she said.
Cody cautioned the outbreak could have been driven by factors unrelated to the variant, such as changes in ventilation or personal protective equipment practices at the hospital.
“The takeaway is not that we need to start worrying about this,” Cody said Sunday. “The takeaway is this is a variant that’s becoming more prevalent, and we need to lean in and understand more about it.”
Chiu, the virologist who conducted the genetic sequencing, said a deeper investigation must be done to determine if the strain is more transmissible like the United Kingdom variant, which is believed to be twice as infectious.
He also raised concerns that a mutation associated with the variant might make it more resistant to vaccines because it occurs in a critical part of the spike protein that is targeted by the vaccines, but he added that the virus must be grown in a lab and tested more fully before any conclusions can be drawn.
Carlos del Rio, a professor of medicine and global health at Emory University, said the rising prevalence of the variant shows the urgent need for more genetic sequencing in the United States and for greater compliance with measures such as wearing masks and avoiding crowds.
“We really need to hunker down because if you are really concerned about mutations, stop transmission,” del Rio said. “The more mutations you see, the more uncontrolled transmission you will see.”
After starting the new year with record high new cases, deaths and hospitalizations, the United States is starting to see signs of slowing spread despite fears of a post-holiday surge that would continue through January. The seven-day average of new infections has slowed since last Tuesday and hospitalizations have started to plateau, according to Washington Post tracking.
Still, Scott Gottlieb, a former Food and Drug Administration commissioner, warned that the advent of more transmissible variants could reverse that progress.
“As current epidemic surge peaks, we may see 3-4 weeks of declines in new cases but then new variant will take over,” Gottlieb tweeted Sunday, referring to the British variant. “It’ll double in prevalence about every week. It’ll change the game and could mean we have persistent high infection through spring until we vaccinate enough people.”