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December 31, 2020

Yes, the Coronavirus Is Mutating—Here's Why You Shouldn't Panic

Yes, the Coronavirus Is Mutating—Here's Why You Shouldn't Panic

Updated on December 30, 2020 at 5:15pm EST.

The first U.S. case of the new coronavirus strain that’s been circulating in the UK has been reported in Colorado. The patient, a man in his 20s, is now in isolation outside of Denver. He has not travelled, and as of December 29, health officials have not identified any close contacts who may have been exposed to the mutant strain of the virus.

“There is a lot we don’t know about this new COVID-19 variant, but scientists in the United Kingdom are warning the world that it is significantly more contagious. The health and safety of Coloradans is our top priority and we will closely monitor this case, as well as all COVID-19 indicators, very closely. We are working to prevent spread and contain the virus at all levels,” said Governor Jared Polis in a news release.

Since the new strain of SARS-CoV-2 was identified overseas, multiple countries quickly announced border closures. Its emergence has prompted worries about a major setback in the fight to control the pandemic. Among the biggest concerns: the potential for greater infectiousness, resistance to the vaccines just now rolling out and the possibility that certain therapies used to manage severe COVID-19, such as monoclonal antibodies (laboratory-made versions of natural antibodies against SARS-CoV-2), would be less effective.

“We really don't know the clinical impact of this,” says Andrew D. Badley, MD, a Mayo Clinic virologist and infectious-disease physician. “I think there's cause for theoretical concern. I think there's cause for additional investigation and study.” 

But it’s not time to panic.

Such shifts are normal. Viruses’ genetic material mutates all the time as part of the process of recopying as the virus reproduces in an infected person. Variants that make the virus more effective are likelier to persist and spread.

Most SARS-CoV-2 mutations are either harmful to the coronavirus or have no effect either way.

The evidence to support concerns about coronavirus mutations isn’t conclusive, and many lessons have already been learned about how to avoid infection—wearing masks, social distancing, avoiding crowded places and confined spaces, increasing ventilation when indoors, avoiding commonly touched surfaces and not touching any part of your face with unclean hands.  

What is known so far
On December 8, 2020, researchers in the UK noticed that one particular strain of SARS-CoV-2, the coronavirus that causes COVID-19, accounted for about half of all infections in the Southeastern English county of Kent. The new variant also showed up in samples collected on September 21 in greater London.

The variant, dubbed B.1.1.7 or VUI-202012/01 (the VUI stands for variant under investigation), has an unusually large number of mutations. Reports range from 14 to 23, which is surprising for a virus that normally accumulates 1 to 2 mutations per month. Several of these mutations appear to be especially important.

One of these mutations, called N501Y, occurs in the spike protein that the virus uses to bind to ACE2 receptors and infect human cells. This mutation appears to allow the virus to bind more tightly to ACE2.

Another, 69-70del, has been linked to the ability to evade neutralizing antibodies. 

A third, the P681H mutation, “may be associated with enhanced entry into the cells,” Dr. Badley says.

With all these mutations and more, early evidence suggests that B.1.1.7 may be better at spreading from person to person than other variants in the UK.

On December 18, the UK’s New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG) expressed “moderate confidence” that the new variant shows a substantially higher transmissibility than other variants. An estimated 50 to 70 percent higher transmission rate has been reported, though this number derives from a mathematical model, not from lab data.

Still unknown as of December 18, according to NERVTAG, is exactly how this might be happening. The age distribution of cases, disease severity, and reinfection rate are also unclear.

Another coronavirus variant has arisen in South Africa that also has the N501Y mutation. That strain, called 501Y.V2, may spread faster and result in higher viral loads, which are linked to more severe COVID-19. More research is needed to know for sure.  

What all this could mean
How will these mutations affect COVID-19 testing, immunity, and vaccination?

First, testing with the polymerase chain reaction method (PCR) is unlikely to be affected, according to Badley.

“Most PCR probes are multiple nucleotides,” he said. “Having a single mutation within a nucleotide probe doesn't really alter the ability to pick it up by PCR testing.

“The bigger concern—and it's a concern, it's not a fact—is, Can it escape antibody neutralization?” Badley adds.

So far, scientists say, it doesn’t seem likely to escape entirely. That is in part because the body develops an array of antibodies against the protein, each slightly different, to increase the odds that one of them will bind to it effectively.

“Those people who make antibodies naturally make multiple different kinds of antibodies, and the antibodies that are out there therapeutically are all different,” Badley says. “While it is possible it could escape some antibodies, I think it's unlikely it'll escape all antibodies.”

To answer this question, lab testing is underway at NERVTAG, according to Badley, and at the Walter Reed Army Institute of Research. 

If some mutant strains are not effectively neutralized by antibody treatments, different antibodies may be selected, Bradley says.

In any case, viral evasion of our immune response is nothing that hasn’t been faced before.

“It may also be that our host immune responses against naturally occurred [SARS-CoV-2] infections may be protective against reinfection for some strains, but not other strains, much as it is for other coronaviruses,” Badley says. “Influenza is that way. And RSV (respiratory syncytial virus) is probably that way. So there's precedent for this kind of differential immune control.”

What about the vaccines being rolled out in record time by Pfizer/BioNTech and Moderna?

These vaccines work by teaching the body to develop an immune response against the coronavirus’s spike protein. Since eight of B.1.1.7’s mutations occur in the gene that encodes the spike protein, some people worry that vaccines may be less effective against it.

But they’re likely to work against the new strain, researchers told the New York Times. Scientists are currently working to confirm this.  

If new mutations do affect the vaccine in the short term, they would almost certainly reduce its efficacy rather than canceling it out entirely. And even a partially effective vaccine is valuable and will help control the pandemic.  

For example, a flu vaccine that’s only 20 percent effective can still save 21 million infections and nearly 62,000 lives if it’s administered to 43 percent of the people who should receive it, researchers have calculated.

The new vaccines’ technology also makes them easy to redesign in response to important mutations. And we have time for such updates: It reportedly would take years for the coronavirus to become entirely resistant to current vaccines.

The mutations aren’t really surprising
Scientists have been watching SARS-CoV-2 mutate for months. In fact, as early as February, they spotted an especially contagious variant with a mutation called D614G, which rapidly became the most common variant in the world.

“Throughout the course of the epidemic, we have heard multiple reports of multiple mutations, and I believe we will continue to see those reports,” Badley says.

This particular variant may have accumulated its large load of mutations over time while hiding out in a person in a weakened immune system, possibly as a result in part of evolutionary pressure from treatment with monoclonal antibodies.

Coronavirus is likely to become less lethal over time, “for a multitude of reasons,” according to Bradley.

Those reasons include the population gradually acquiring immunity through various means, as well as viral mutation and evolution, he explains.

“And then our ability to treat coronavirus disease today is vastly better than where it was a year ago,” he adds. “We’re already seeing declines in mortality in multiple centers.”

Thanks to evolution and the vast number of people being infected, mutations and new strains of SARS-CoV-2 will continue to emerge in the coming months. But the world is better equipped now than ever before to prevent and manage COVID-19.

Medically reviewed in December 2020.

Sources:
Colorado Governor Jared Polis. “Gov. Polis and State Public Health Officials Announce First Case of COVID Variant of COVID-19 in Colorado.” Dec 29, 2020.
Science. “Mutant coronavirus in the United Kingdom sets off alarms, but its importance remains unclear.” Dec 20, 2020.
Virological. “Preliminary genomic characterization of an emergent SARS-CoV-2 lineage in the UK defined by a novel set of spike mutations.” Dec 19, 2020.
New and Emerging Respiratory Virus Threats Advisory Group. “NERVTAG meeting on SARS-CoV-2 variant under investigation VUI-202012/01.” Dec 18, 2020.
African Union. “Statement on new SARS-CoV-2 variant with multiple spike protein mutations.” Dec 21, 2020.
Burgess Stephen, Smith David, Kenyon Julia C, Gill Dipender. Lightening the viral load to lessen covid-19 severity BMJ 2020.
Pratha Sah, Jan Medlock, Meagan C. Fitzpatrick, et al. Optimizing the impact of low-efficacy influenza vaccines. Proceedings of the National Academy of Sciences May 2018, 115 (20) 5151-5156.
Ralph S. Baric, Ph.D. Emergence of a Highly Fit SARS-CoV-2 Variant. New England Journal of Medicine. Dec 16, 2020.
SA Kemp, WT Harvey, RP Datir, et al.  Recurrent emergence and transmission of a SARS-CoV-2 Spike deletion ΔH69/V70. bioRxiv Dec 14, 2020.

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