Here’s how variants of the COVID-19 virus work
The delta variant of SARS-CoV-2, the virus that causes COVID-19, grabbed the headlines as it quickly became the most prevalent strain in America. But other variants of the virus still exist, and more will form as the virus continues to spread.
Why do viruses mutate?
Viruses mutate and form new variants “to try to survive better,” according to David Wohl, professor of medicine specializing in infectious diseases at the University of North Carolina School of Medicine.
The human immune system creates many barriers for viruses to pass through once they enter our bodies, Wohl said. Mutation is a matter of survival – the viruses that are able to get through these immune attacks, get out into the air, enter someone else’s body and continue to spread will be the viruses that survive. .
“Viruses are selected for the survival of the fittest,” Wohl said. “And by more fit, it usually means more ‘eye-catching.’ Maybe it lasts longer in the nose and throat and can spread to more people.”
Viruses don’t mutate to evade drugs and vaccines, but rather the human immune system, Wohl said.
“It’s no surprise over the past year and a half, when we have done next to nothing to try to control the virus except vaccination, and most of the planet is far from ‘to be vaccinated, for viruses to run wild and to escape our immune systems more and more, ”Wohl said.
What makes the variants different?
Wohl said the main changes in SARS-CoV-2 variants are differences in spike proteins, “the spiky part on the outside of the virus that attaches to receptors in our cells.”
“The spike proteins can change in small ways, but in a way that helps escape a system that might have antibodies to the spike protein,” Wohl said.
Variants can be “like a chameleon,” he said. With different spike proteins, the antibodies in the vaccine or that the body makes against a previous version of SARS-CoV-2 will not recognize the virus and move on.
What are the variants of SARS-CoV-2 besides delta?
The four main variants of the SARS-CoV-2 virus currently are alpha, beta, gamma and delta variants, but others exist.
The alpha variant was first detected in the UK in September 2020. It was first detected in the US in December 2020. The beta variant was initially detected in South Africa in December 2020 and has was found in the United States at the end of January. . The gamma variant was initially identified in Brazil in early January and was found in the United States the same month.
There are other variants as well, such as the iota variant first identified in the United States and the lambda variant first seen in Peru, according to Wohl.
He stressed that the variants do not necessarily come from the places where they were first identified.
“For example, even though (alpha) is a variant of the virus that has been identified in the UK, that doesn’t mean it started in the UK,” he said. “It just means that they have the labs and have done the sequencing to detect it. It could have come from another place that did not do any investigation to understand that it was a different variant.
The alpha variant has a mutation that helps the virus bind more tightly to the cells it infects, which improves the chances of the virus successfully infecting the cell.
Beta carries a mutation that makes it more contagious, and another that helps it bypass a person’s immune system, although there is no proof it causes more serious illness in most people who are infected.
Likewise, the gamma variant has mutations that allow it to attach to human cells more easily, although it is not as transmissible as alpha or delta.
What is the most common variant in the United States today?
Alpha has become the dominant variant in the United States in April, and it stayed that way until June. Now the highly transmissible delta variant is the most common strain of the virus circulating in the country.
Wohl said he “wouldn’t be surprised if very soon Delta would take over completely like it did in the UK”
While North Carolina is still seeing cases of a mix of variants, Wohl said more and more cases are turning out to be from the delta variant every day.
The News & Observer reported that in the week to June 19, about 30% of new cases were estimated to be due to the delta variant in North Carolina. This rate was only 0.7% a month earlier.
How can we stop the variations?
Wohl said there have been shifting variants of the virus since the start of the pandemic.
“We’ve gone from what we call the ancestral variant of Wuhan to a somewhat different and maybe a little more eye-catching variant,” he said. “It just took a mutation to happen.”
If the virus continues to spread, variants will continue to appear.
“As long as people harbor the virus and reproduce it, this will continue to happen. That’s the problem, ”he said. “Once you stop replication and propagation, you won’t have any more variants. “