Newly mutated strains of the new coronavirus detected around the world – such as those that are ravaging the UK and South Africa – are increasing the fear of becoming dominant here in the United States as well. Americans now have a freshly grown strain to worry about – and public health experts suspect it may have been the cause of the most recent outbreak in Southern California.
Recently, American scientists were looking for signs of the UK coronavirus variant, known as B 1.1.7, in California, when they found something different. Strain B 1.1.7 of the coronavirus has a transmission rate of 50 to 70 percent higher and can be more deadly, which has led to studies to see how much it has infected the population of the United States. However, while searching for B 1.1.7, scientists found a new strain that has peculiar mutations, which is now being called CAL.20C. According to an article published by Cedars-Sinai researchers, which has not yet been peer-reviewed, the new SARS-CoV-2 strain appears to be responsible for at least 36% of COVID-19 cases in the Los Angeles area and 24 % in Southern California in December 2020. This correlates with a large increase in coronavirus infections in Southern California at the time.
“After an analysis of all publicly available data and a comparison with our recent sequences, we see a dramatic increase in the relative percentage of the CAL.20C strain starting in November 2020,” the researchers wrote in the newspaper. “The predominance of this strain coincides with the increase in the rate of positivity seen in this region.”
In mid-January, scientific modeling estimated that one in three LA county residents had been infected with the coronavirus. While the rise of Southern California appears to be slowing, scientists are concerned that a further The CAL.20C strain mutation, called L452R, has a structural change similar to the variant found in South Africa.
As Salon previously reported, the 20C / 501Y.V2 variant, also known as strain B.1.351 – which emerged in Durban, South Africa – is alarming because the mutation occurs in the so-called “external Spike” of the virus or in proteins in the outer layer of viruses that resemble thorns like those of a sea urchin. Mutations in Spike have a chance to disguise the appearance of the virus to the immune system of someone who already has antibodies to the coronavirus, which can make it easier to bypass immune protection. The L452R may be similar to the South African strain in this respect.
“The mutation of the S L452R protein is within a known receptor-binding domain that has been found to be markedly resistant to certain monoclonal antibodies to the spike protein,” wrote the Cedars-Sinai researchers in the article. They note that mutations in the spike protein may be “resistant” to antibodies from previous coronavirus infections with other strains.
But scientists say it is not yet time to panic, as we are not sure whether this variant of the new strain is resistant to vaccination or not. Identifying the variant is the first step for many to understand how and if that variant is more transmissible – or, worse, if it can change how someone’s immune system responds to a vaccine.
Dean Blumberg, head of pediatric infectious diseases and an associate professor in the Department of Pediatrics at the University of California, Davis, told Salon he would characterize this article as a “preliminary report”. The coronavirus, he said, mutates naturally every two weeks or more.
“So, you will always have several different mutations and strains,” said Blumberg. “Some of these strains make mutations that will be minimal and will make very little difference in terms of how they infect people in terms of the rate or severity of the infection, and others are more significant.”
Blumberg echoed concerns about several of the mutations for the CAL.20C strain that occur mainly in the protein Spike.
“This could make them more efficient at binding, transmitting and infecting cells,” said Blumberg. “But as I read this article, it was not clear to me whether mutations make this virus more suitable or not, which is why I’m still not sure what it means.”
Blumberg added that it is “good news” that we are encountering these variants. Before, the United States was left behind in sequencing the coronavirus – hence the discovery of variant B 1.1.7 in the United Kingdom, which was preceded by its discovery in the United States. Furthermore, it is not clear whether this new variant is behind the rise in Southern California.
“We don’t know if this is just a coincidence that this is just the current variant being transmitted or we don’t know if it could be because this variant is being transmitted more efficiently, which is why there is an increase in cases,” said Blumberg. “We need to investigate this.”
Other scientists agree.
“It may have contributed to this increase, or simply followed by the tour,” said Dr. Charles Chiu, a laboratory medicine specialist at the University of California-San Francisco, to the Los Angeles Times.
When it comes to prioritizing variants and which ones are of most concern, Blumberg said “there are many things to worry about”, but like the variants found in the UK and South Africa, which we have more information about right now. Blumberg said more information is needed before the California variant reaches the same level of concern.
“They still don’t know much about this variant, so it’s not reaching that level of concern,” he said. “Just because we don’t have that information.”