Waiting for the virus variant

two types of more contagious mutations of COVID-19 reach Nevada

IMAGE/PIXABAY: COVID-19 mutates into variants of the original virus that often are more contagious.
UPDATE, Feb. 22, 2021: Southern Nevada has reported six known cases of a more contagious UK COVID-19 variant and detected that genome in Las Vegas’ wastewater. On Feb. 18, Washoe County officials confirmed that the South African variant was detected in a sample traced to a person who traveled from South Africa and began showing symptoms of COVID-19 when arriving in Reno. 

There’s no large-scale federal effort to track the U.K. variant, which appears to be significantly more contagious and that some scientists theorize can spread through a population 56% faster than the original form of COVID-19. Nevada is among a handful of states that can – and do – test for the variant.

Some scientists’ models predict the mutation will become the most common strain in the U.S. by late March. That has heath officials again worried that a surge in cases could overwhelm hospitals’ ability to treat patients and result in rationed care in some areas.

Researchers in the U.S. and Europe say the strain doesn’t seem to be more deadly or cause more severe symptoms than the original form of the virus, but it is apparently less forgiving of lapses in personal precautions than the current form of SARS-CoV-2, the virus that causes COVID-19.

U.K. strain more contagious

“(That) means that people need to continue with the measures of mask wearing, hand washing and physical distancing that we know work,” said Dr. Mark Riddle, professor and associate dean of clinical research at the University of Nevada, Reno, School of Medicine. “While we don’t know exactly how the new variant renders the infection more contagious, such personal protective measures provide broad protective ability and thus need to be continually employed in our communities.”

In about two months, the variant, dubbed B.1.1.7, went from being a newly-discovered mutation to an increasingly dominant strain in Britain. By mid-December, more than 75% of new cases in London were from that form of the virus. The spread came even though the U.K. was under pandemic restrictions.

As of Jan. 13, only 76 infections with the variant had been detected in the U.S. But models predict it will crowd out other strains and become the most common cause of COVID-19 by March, according to Summer Galloway, PhD, of the Centers for Disease Control and Prevention, in a paper published in in Morbidity and Mortality Weekly Report.

Exponential spread expected

In the absence of a coordinated detection system, some scientists say the mutated virus may already be responsible for 1-in-1,000 cases in the U.S. They expect states to soon see the same sort of exponential spread witnessed in the U.K.

So far, it appears the COVID-19 vaccines now being dispensed will guard against infection from the UK variant and others so far seen in the U.S. The arrival of the U.K. variant and other new forms of the virus underlines the importance of getting the vaccines into as many arms as possible as fast as possible, public health officials said.

There is no federal program for strategic surveillance of the virus’ mutations and some states aren’t yet doing the gene sequencing necessary to detect the new strains. Nevada, meanwhile, has been testing for the variant.

Nevada lab looks for mutants

Dr. Mark Pandori, director Nevada State Public Health Laboratory and associate professor of Pathology and Lab Medicine at the University of Nevada, Reno, School of Medicine, said the lab has sequenced more than 300 positive cases of the virus to get a handle on the variants spreading in Nevada. Sequencing is a method of defining the DNA of the samples.

“We used to do (the samples) in ‘batches,’ but now we have the ability to sequence routinely, on a daily basis, and we get about 25-30 high quality genomic sequences a day now, from positive cases,” Pandori wrote in an email to the Reno News & Review. “This has allowed us to really ramp up surveillance from a genetic perspective.”

The Nevada lab also is able to screen for the U.K. variant without going through the sequencing process. “For (that variant), we have a sort of trick… (We screen) and if we see a certain signal pattern we can sequence that specimen to confirm for that variant.  We have done at least 400 more positives from Dec. 19 onward and none of them were candidates for the variant.”

IMAGE/CDC LIBRARY: This illustration, created at the Centers for Disease Control and Prevention, reveals the makeup of the virus that causes COVID-19. It identifies the proteins that make up the coronavirus. The protein “spikes” that adorn the outer surface of the virus are targeted by the new vaccines.

Vaccines target ‘spikes’

Pandori said the genomic sequencing will continue, “daily, we hope, for as long as the pandemic continues.” The specifics of the technique are the subject of a paper now in review at the Journal of General Genetics, he said.

The persistent mutations of the virus don’t appear to be occurring in critical areas of the protein “spikes” of the virus.  The spike proteins are associated with both vaccine design and the production of antibodies kicked off by the vaccine that fight future infection, according to current reports.

Riddle said research into vaccines’ protective ability on future mutations is unknown, but he said, “historically, but not always, evolutionary pressures direct mutations towards viruses becoming less lethal but more communicable in pandemic situations. However, to answer this question (about future mutations) would require a crystal ball as we just don’t know enough.”

Research continues

Because the vaccines target those “spikes” on the virus, which it uses to latch on to its hosts, the virus’ natural selection process ought to lean toward keeping that feature. He said it’s unlikely that mutations that reduce the virus’ ability to infect its hosts would prosper. Even if a mutation did change part of the spikes’ receptors, antibodies produced by the vaccines are directed at different parts of the virus’ receptors.

Still, Riddle said, a rogue mutation is possible and something the scientific community is actively looking for. So far, though, the news is encouraging. He noted that a study published this month suggests “that the (UK) mutation did not alter the activity of antibodies from people who got the Pfizer and BioNTech vaccine. “Lots more data should be coming out soon looking at this problem,” he said.

Vaccines should remain effective

In general, researchers are hopeful that the mutations in the variants won’t “substantially weaken the performance of vaccines,” according to an article in the journal “Nature,” published on Jan. 7. 

“The (vaccine) shots tend to elicit whopping levels of neutralizing antibodies, so a small drop in their potency against the variants might not matter. Other arms of the immune response — T-cells, for example — that are triggered by vaccines might not be affected,” according to the article. The article concluded with a quote from Jeremy Luban, a virologist at the University of Massachusetts Medical School in Worcester:

“If I had to bet right now, I would say the vaccines are going to remain effective for the things that really count — keeping people from getting deathly ill.”

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