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Illustration of a coronavirus under the microscope.
Image: picture-alliance/Newscom/CDC

Concern about coronavirus mutations in New York, California

March 3, 2021

Mutations that have arisen in the US are spreading rapidly. Are they more contagious? And will the vaccines still be effective against them?


Since health authorities have begun sequencing positive COVID-19 cases more carefully — i.e., genetically examining test results — they have also found more and more mutations.

Most of those mutations are insignificant. But there are a few variants that researchers and officials are concerned about, in part because they are more contagious and because existing vaccines could be less effective at protecting against them.

A border checkpoint at the Czech-German border
No more freedom of movement. Some countries are trying to stem the spread of mutations by closing borders.Image: Odd Andersen/AFP

In addition to the variants identified in BritainSouth Africa, and Brazil, there are two more variants causing concern in the United States that appear to have evolved there. 

Rapid spread

In November, researchers first noticed a mutation in New York City called B.1.526. Since then, this variant has spread rapidly in the metropolis and across the state. By mid-February, it had been detected in 12% of all samples in New York that were gene sequenced. 

This variant has also appeared in other countries such as Denmark.

A woman wearing a face mask is jogging before the background of the Golden Gate Bridge
The Californian variant, CAL.20, is believed to be more contagious than the original virus, but not as dangerous as the British variant.Image: Jeff Chiu/AP Photo/picture alliance

The so-called California variant, first detected in July 2020, has also spread rapidly. Meanwhile, the two similar types, B.1.427 and B.1.429, of the California variant can be found in about a quarter of the gene-sequenced samples in California.

What do we know about the two US variants?

So far, we don't have thorough reliable data on these variants. The California variant, CAL.20C, is said to be more contagious than the original SARS-CoV-2 virus. In swabs taken from infected individuals, the viral load in the samples was found to be about doubled. But it is less infectious than the British mutant B.1.1.7, which has now been detected in a large number of countries, including Germany. The existing vaccines are thought to be somewhat less effective against the Californian virus variant, but still sufficient to protect patients from a severe course of COVID-19.

The New York virus variant, B.1.526, is similar to the South African variant, B.1.351, which has already been detected in more than 40 countries, and also shows similarity to the Brazilian variants, P.1 and P.2, which have been detected in more than 20 countries, most recently in the United Kingdom.

It is still unclear whether the New York variant is more contagious or dangerous, and whether existing vaccines are still sufficiently effective against this variant.

New software helps in the search

Finding the respective variants is only possible if you know what to look for. Although we now know the genome of SARS-CoV-2, the virus is 29,903 nucleotides-long, which is far too long to make it possible to quickly identify which variants might make it more infectious among the 611,000 genomes now stored at the GISAID database.

The mutations were found using new software called Variant Database (VDB) developed at the California Institute of Technology in Pasadena, by a team led by Pamela Bjorkman. It focuses on changes in the spike protein. 

A man gets a swab test in Johannesburg
A mutation called E484K hass been found in both the South African and the Brazilian variant.Image: Luca Sola/Getty Images/AFP

The potentially dangerous mutation E484K, which is present in B.1.351 and P.1, alters the receptor-binding domain of the spike protein, and this is where the antibodies with the strongest neutralizing effect attack.

A cause for concern, but not for panic

The tip of the spike protein is also altered in the New York variant. Understandably, this has caused some worry, the epidemiologist Wafaa El-Sadr of Columbia University told the German public broadcaster, ARD. "These changes can result in the spike protein being able to attach itself better. Or that the virus can reproduce more quickly. Or that it cannot be fought by the antibodies through our vaccines," he said.

But, until detailed and robust data on the US variants is available, these observations remain speculative and there is no need to panic, said  Dave Chokshi, commissioner at the New York City Department of Health and Mental Hygiene. As of yet, there isn't any evidence to show that it spreads faster, whether it's making people sicker or whether it reduces the effectiveness of the vaccine, he said.

This article has been translated from German.

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