Variants of Covid are inevitable as long as the virus continues to spread, doctors say

The virus that causes covid-19 has mutated again and again, and experts say new variants will continue, partly because of the nature of the virus and also because large swaths of the population choose not to be vaccinated.

“Should we expect more variants? The answer is yes,” said Dr. Mohamed Yassin, Director of Infection Control at UPMC Mercy. “How many? Probably too many. There will be a lot.”

The very nature of the coronavirus, he said, makes it prone to mutate.

There are two main types of viruses, Yassin explained: the DNA type and the RNA type. Each time the DNA virus divides, it makes an exact copy of itself. This perfect copy process does not occur in RNA viruses, which means there is a chance of change every time the virus replicates. The virus that causes covid-19 is an RNA virus. The flu too.

“It’s no different than what we see with the flu virus every year,” said Excela Health chief medical officer Dr. Carol Fox. “It changes often, and that’s why we have to get the flu shot every year: because there are different variants.”

Whether a variant is more severe or more transmissible depends, for the most part, on chance, Yassin said. Viruses can often be changed or redesigned in a lab, he said, “but in nature, these changes are random.

“It’s almost impossible to know what the next strain will be,” he said. “Is it going to be more virulent or less? I don’t think we can know.

The fact that many people are not vaccinated could exacerbate the problem, Yassin said.

Nationwide, just under 222 million people are fully immunized, about two-thirds of the population. About 47% received a booster dose, according to the Centers for Disease Control and Prevention.

In Pennsylvania, about 66% of the population is fully vaccinated and 32% have a booster dose, according to the state Department of Health.

The proportion of people vaccinated in Allegheny County is higher than the statewide: 73% are fully vaccinated and nearly 38% have a booster dose, the data shows. In Westmoreland County, the numbers are lower than the state as a whole: 60% are fully vaccinated and 30% have received a booster.

“If you don’t have a lot of (viruses) circulating, you’ll have a much lower chance of mutation and new variants – that’s absolutely true,” he said.

He said it’s an important part of the public health messaging that has accompanied and continues to accompany the pandemic.

“It’s not just about the person, you or me. It’s about us,” he said. “So yes, if we don’t all get the infection, if we all have a lot less activity because of vaccination, the mutation rate will definitely go down.”

Variations over time

At least five variants of the virus have been identified, some of which had their own subvariants. Currently, omicron and its subvariants are the dominant strain circulating in the world. The first case of covid-19 attributed to the omicron variant was detected in the United States in early December, and it was found to be even more transmissible than its highly infectious predecessor, delta.

The omicron variant was later named a variant of concern, which the World Health Organization defines as a variant that shows increased transmissibility or a detrimental change in the epidemiology of covid-19; an increase in virulence; or is less affected by public health measures such as vaccinations and mitigation measures.

Omicron caused a massive increase in cases in late 2021 and early 2022. Although it has been shown to cause less severe disease than previous variants, its quick and easy transmission has resulted in an influx of hospitalizations and an increase in deaths.

Since then, a number of omicron subvariants have been detected, including BA.2 and BA.2.12.1. In early June, the BA.4 and BA.5 subvariants were estimated by the CDC to account for about 13% of new cases, up from 7.5% the previous week, according to Yale Medicine.

Before omicron, there was the delta variant. It was first identified in Indiana in late 2020, according to Yale Medicine, but its surge in the United States didn’t begin until fall 2021, leading to an increase in cases after months of decline. Some studies have suggested that the delta variant is 80% to 90% more transmissible than previous variants, and has been found to cause significantly more severe disease in those vaccinated.

Alpha, beta, and gamma variants circulated in 2020, each with varying degrees of higher transmissibility. They were named variants of interest by the World Health Organization at the time.

The World Health Organization has also named a number of what it calls variants of interest: variants that show predictable changes and cause significant community transmission. Among them are epsilon, zeta, eta, theta, iota, kappa, lambda and mu.

“We didn’t name these variants of concern, but they were more transmissible variants,” said Dr. Kevin McCarthy, assistant professor of molecular genetics and biology at the University of Pittsburgh. “What we saw when immunity started to build in populations, viruses were able to mutate and start to overtake some of that immunity.”

How exactly this happens, he said, is not entirely clear.

“The virus is going to adapt as it passes through hundreds of millions and billions of people – goes on and infects and then reinfects people,” said McCarthy, a fellow at the Pitt Center for Vaccine Research. “So whatever the virus can do to enable it to do better, eventually it will figure out how to do those things.”

It’s a process that experts still don’t fully understand, he said.

It’s possible – but not certain – that some mutations occur in people with weakened immune systems who have persistent infections. As the body tries to fight off the virus, McCarthy explained, the virus tries to replicate itself. To achieve this goal, the virus can evolve to infect cells more efficiently, he said, and can even evolve to evade antibodies created during illness.

He compared it to playing the lottery every week.

Each time the virus reproduces, it buys a lottery ticket. Most of the time, nothing comes of it, he says, “but once in a while someone wins the Mega Millions.”

“We will live with this”

As has been the refrain since the pandemic began more than two years ago, experts say there’s no way to know exactly what the future holds.

“That’s the million dollar question,” McCarthy said.

What he does know is that there is no indication that covid-19 is going away.

“We’re going to live with that,” he said. “What that looks like, I think we’re still not sure.”

McCarthy said it’s unclear if the virus will be seasonal like the flu has been in recent years, but there will likely be spikes and dips dictated by human behavior.

He said the best-case scenario would be one or two dominant variants at a time, as opposed to a myriad of mutations circulating. That, he said, would make it harder to figure out how to handle the virus long-term. For now, companies are working on covid vaccines that are in the same vein as flu shots in that they target three or four strains in a single dose.

Fox said she thinks covid-19 will end up looking more cyclical.

“I think the hope is, or what you would expect to see, that these peaks and valleys get smaller,” she said. “Instead of… high highs and low lows, the variations will continue, but they will look more like little dots.”

It depends on human behavior, she noted. She said that’s why colds and flu cases typically start in the fall when kids are back in school and more people are staying indoors for longer periods with no windows open.

“It has to do with what’s going on in our environment,” she said. “There are more opportunities for germs, viruses and bacteria to spread.”

Yassin also said he thought the virus could take on a more seasonal appearance, but noted that the real future of covid illness, hospitalization and death hinged on vaccinations.

“The vaccination rate in the United States is really much lower than in other Western countries,” he said. “It puts us in a more vulnerable position. We have had, like in the United States, so many cases, we have had so many deaths. I wish we could convince more people to get vaccinated for themselves and for the good of the community as well. »

Megan Guza is editor of Tribune-Review. You can contact Megan at 412-380-8519, mguza@triblive.com or via Twitter .


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