Public health experts have been learning more and more about coronavirus variants as the virus continues to mutate and spread across the globe. But while B.1.1.7 (the U.K. variant), B.1.351 (the South African variant), and P.1 (the Brazilian variant) have received a lot of attention, another has emerged right here in the U.S.
B.1.427/B.1.429, two forms collectively dubbed the “California variant” as they share three key mutations, has spread wildly since its initial detection in July 2020 in Los Angeles County; in fact, experts predict the “homegrown strain” will be responsible for 90% of the state’s coronavirus infections by the end of March, the Los Angeles Times reports.
The Center for Disease Control Prevention (CDC) has also named them as “variants of concern,” alongside B.1.1.7, B.1.351, and P.1. Early research suggests this particular variant may be more infectious and could potentially cause more severe disease than the initial, dominant strain of SARS-CoV-2 (a.k.a. the novel coronavirus). Here’s what experts know so far.
What is B.1.427/B.1.429 and where did the variant come from?
Researchers at the University of California, San Francisco (UCSF) have analyzed its mutations and released a few key findings.
The California variant has three mutations in the spike protein of SARS-CoV-2, which signals that it may be more infectious than the initial, dominant novel coronavirus strain, the researchers say. The coronavirus uses the spike protein to latch onto human cells, where it then replicates and infects other cells, explains infectious disease expert Amesh Adalja, M.D., senior scholar at the Johns Hopkins Center for Health Security. Thus, “changes in the spike protein are likely to change the ability of the virus to bind to human cells. That may make a virus more efficient.”
It’s unclear exactly where the variant came from, but recent research conducted by UCSF and the Chan Zuckerberg Biohub found that it is prevalent—53% of 630 positive COVID-19 cases detected in San Francisco’s Mission District in mid to late January were represented by a key mutation known as L452R, which is shared by B.1.427 and B.1.429. Another preprint study conducted by researchers from Cedars-Sinai Medical Center found that there has been “dramatic growth” of the California variant in the state since November 2020.
What does the CDC say about the California variant?
The CDC recently announced that it is classifying major variants as they emerge and grouping them into the following categories: variants of interest, variants of concern, and variants of high consequence.
Variants of interest, which include the B.1.526 variant that emerged in New York in November 2020, have “specific genetic markers” that are predicted to impact transmission, diagnostics, and treatments, along with evidence that show they’re the cause of an increased proportion of cases or outbreaks. However, the CDC says, these variants have “limited prevalence” or expansion in the U.S. or other countries.
Variants of concern, which the California variant has been labeled as, are variants that have evidence of an increased risk of transmission, more hospitalizations or deaths, a “significant reduction” in the ability of antibodies developed against the virus to fight the virus, and reduced effectiveness of treatments.
The CDC has not yet identified variants of consequence, which have “clear evidence” that prevention measures or medical treatments are not effective, compared to previously circulating variants.
Both B.1.427 and B.1.429 are 20% more transmissible than the original SARS-CoV-2 strain and have a “significant impact” on the ability of some treatments authorized by the FDA to treat COVID-19, per the CDC. They also cause a “moderate reduction” in vaccine performance.
Has the variant been detected beyond California?
The CDC has not released official numbers yet. Research so far has largely focused on the state of California, but that will likely expand over time. However, variant tracker Outbreak.info, a project from the Su, Wu, and Andersen labs at Scripps Research, reports that B.1.429 has at least been detected in a majority of states.
How contagious is the California variant? And does it cause more severe COVID-19?
The researchers behind the aforementioned preprint study also published a research letter in JAMA about their results. They found that most strains of coronavirus in Southern California came from the 20C clade before October 2020. (A clade is a group of viruses that came from the same source.) This clade was the one that took hold in New York in early 2020, when the pandemic first started to ramp up in the U.S.
But the researchers found that the California variant slowly started to spread in the state in late fall. By January 2021, the California variant made up 35% of all COVID-19 cases in the state, and 44% of all coronavirus cases in Southern California. “This rise happened at a time when California was surging,” explains David Cennimo, M.D., assistant professor of medicine-pediatrics infectious disease at Rutgers New Jersey Medical School in New Jersey. “So, it is implied that the variant causes a greater prevalence of cases, as well as a greater percentage of cases.”
Preliminary UCSF research that has not yet been published analyzed a group of more than 300 COVID-19 patients and also discovered a link between B.1.427/B.1.429 and more serious illness. The data, which was shared with Science, found that those who were infected with the California variant were nearly five times more likely to be admitted to the ICU and 11 times more likely to die compared to patients who carried other viral strains, even after adjusting the numbers to account for differences in age, gender, and ethnicity.
Are the available COVID-19 vaccines still effective against the California variant?
Some preliminary lab studies suggest the California variant may be less susceptible to infection-fighting antibodies in the blood of people who received the Pfizer-BioNTech or Moderna vaccines, Science reported, but much more research is needed before any concrete claims about efficacy can be made.
However, the experts we talked to are confident in the available vaccines. Dr. Adalja anticipates that the California variant will not be a problem, as long as people receive both doses. “It’s very difficult for a variant to completely escape the vaccine,” he says, meaning that even if the vaccine isn’t as effective against this particular variant as it is against the original SARS-CoV-2 strain, it can still be protective against severe forms of COVID-19. “The solution is vaccination,” he says.
Dr. Cennimo agrees, but emphasizes that we will only know more with time and further study. “I would think the vaccines should still be effective [against the California variant] since they have been doing well against other variants,” he adds.
Should you be concerned about the California variant? What’s the best way to stay safe?
Experts say the California variant is unlikely to be the only homegrown variant. “There are very likely different variants in the U.S.,” says Jennifer Surtees, Ph.D., associate professor of biochemistry and director of the Genome, Environment, and Microbiome Community of Excellence at the Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo.
In fact, a new variant was recently detected in Ohio. “The fact that multiple lineages accumulated similar mutations indicates that these mutations might have a selective advantage,” she says. That’s why, Surtees says, it’s important for experts to track SARS-CoV-2 cases—and their genetic makeup—across the country.
Until researchers know more, now is not the time to let up. Even though cases are now hitting a plateau across the country, more than 530,000 people have lost their lives to this virus, per the most recent CDC data. The same rules of COVID-19 prevention still apply: Continue to practice social distancing, wear a well-fitting, multi-layer mask when you’re around people from outside your household, and keep washing your hands well and often.
This article is accurate as of press time. However, as the COVID-19 pandemic rapidly evolves and the scientific community’s understanding of the novel coronavirus develops, some of the information may have changed since it was last updated. While we aim to keep all of our stories up to date, please visit online resources provided by the CDC, WHO, and your local public health department to stay informed on the latest news. Always talk to your doctor for professional medical advice.
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