Scientists in California are increasingly worried about the state's "homegrown" coronavirus variant, with studies now showing that the variant is more transmissible than earlier strains and may be more resistant to current vaccines, according to news reports.
The variant, known as B.1.427/B.1.429, first emerged in California last spring but didn't show up on scientists' radar until this winter, when cases of the variant rapidly took off in the state, according to The New York Times. However, scientists weren't sure if the variant was indeed more contagious than previous strains or if it became more common simply by chance — for instance, through a few superspreading events.
In a new study, which has not yet been published in a peer-reviewed journal, researchers analyzed 2,172 virus samples collected in California between September 2020 and January 2021. They found that although the variant hadn't yet shown up in September, by January, it had become the predominant variant in California, with cases doubling every 18 days, The New York Times reported.
What's more, lab studies found that the variant was 40% better at infecting human cells compared with earlier strains, according to The New York Times. In addition, people who tested positive for the California variant had twice the viral load (or levels of the virus) in the nose and throat than people infected with other versions of the virus. This may mean that people infected with the California variant can spread it more easily than people infected with other strains, according to the Los Angeles Times.
The researchers said their findings mean that B.1.427/B.1.429 should be considered a "variant of concern" similar to the variants that emerged in the United Kingdom, South Africa and Brazil.
"The devil is already here," study lead author Dr. Charles Chiu, a virologist at the University of California, San Francisco, told the LA Times. "I wish it were different. But the science is the science."
Lab experiments also found that antibodies in people who had been infected with other strains of the novel coronavirus or who had been vaccinated against COVID-19 were less effective at "neutralizing" or disabling the California variant.
Still, the California variant may not be as successful as the South African variant in evading current vaccines. In lab studies, the South African variant elicited sixfold lower levels of antibodies than the levels produced in response to other strains, Live Science previously reported. But the levels of antibodies produced in response to the California variant were just twofold lower, the LA Times reported.
There is also very early evidence that the California variant may be deadlier than other strains. When Chiu and colleagues analyzed about 300 cases of B.1.427/B.1.429 in San Francisco, they found that those infected with this variant were much more likely to die than those infected with other coronavirus strains. But because of the small sample size (only 12 people died overall), the results may not be statistically meaningful.
Some researchers who were not involved in the new study said the California variant did not seem to pose as much of a threat as other coronavirus variants. "It's not as big a deal as the others," William Hanage, an epidemiologist at the Harvard T.H. Chan School of Public Health in Boston, told The New York Times. He noted that the California variant has not seemed to take off in other parts of the country or the world, while B.1.1.7 (the U.K. variant) seems to quickly take over wherever it is introduced.
A study released earlier this month estimated that B.1.1.7 is up to 45% more transmissible than earlier strains in the U.S., according to CNN. Early data from California suggests that B.1.427/B.1.429 may be up to 24% more transmissible than earlier strains, The Los Angeles Times reported.
Studies in the coming weeks will provide a better understanding of just how big a problem B.1.427/B.1.429 poses and whether it will win out over other coronavirus variants that have already turned up in the state, including the U.K. variant and the South African variant, The New York Times reported.
Originally published on Live Science.
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Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.