February 15, 2021

By Marion Renault

The Associated Press

How are experts tracking variants of the coronavirus?

Scientists are scanning virus samples taken from infected people to look for mutations, through a process called genome sequencing. It’s the same method researchers have been using for years to study bacteria, plants, animals, and humans.

Around the world, researchers have sequenced more than 500,000 genomes of the COVID-19 virus to date.

Viruses can mutate as they make copies of themselves after infecting a person. By sequencing virus samples over time, scientists can look for recurring changes in the genome.

"If we don’t know these things, we’re running blind," said Sara Vetter, assistant lab director for the Minnesota Department of Health.

Most mutations are meaningless, but others can make a virus more contagious, deadly, or resistant to vaccines and treatment. Health experts are primarily concerned about three variants first detected in the United Kingdom, South Africa, and Brazil. They seem to spread more easily and research is underway to see if they cause more serious disease.

Evidence suggests that current vaccines still work against the variants though perhaps not as well against a mutated version that first appeared in South Africa.

Countries vary in their genomic surveillance. Britain, for example, sequences about 10% of specimens positive for the coronavirus, compared to less than 1% in the U.S.

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By Marion Renault

The Associated Press

AP Illustration by Peter Hamlin

How many variants of the coronavirus are there?

There are many circulating around the world, but health experts are primarily concerned with the emergence of three.

As a virus infects people, it can mutate as it makes copies of itself. Some mutations can be harmful to a virus, causing it to die out. Others can offer an advantage and help it spread.

"Not every mutation is created equal," said Mary Petrone, who studies infectious diseases at Yale University. "The virus is going to get lucky now and again."

Monitoring variants is important because of the possibility that they could make vaccines and treatments less effective, or change the way they infect people.

A mutation early in the pandemic fuelled the spread of the virus around the world, but there had been no notable changes since — until recently, said Ohio State University biologist Daniel Jones.

One of the three main variants experts are watching was discovered in the United Kingdom late last year and has been detected in dozens of countries since. Health officials initially said it didn’t seem to cause worse disease, but some newer information suggests it might — that remains unknown at the moment. It does appear to spread more easily, which could lead to more hospitalizations and deaths.

The variant might become dominant in the U.S. by March 2021, according to the Centers for Disease Control and Prevention.

Other variants first detected in South Africa and in Brazil also appear more contagious, experts say.

Data so far suggests current vaccines should still protect against these variants, though there’s some concern their effectiveness may be slightly diminished. There is some evidence that some antibody treatments may be less effective against certain variants.

There are ways to adjust vaccines and treatments to maintain their effectiveness, said Dr. Anthony Fauci, the top U.S. infectious disease expert.

The emergence of variants is linked to ongoing surges since infections give viruses the chance to mutate and spread. It’s another reason experts stress the importance of wearing face coverings and social distancing.

"The fewer humans carrying the virus, the fewer opportunities it has to mutate," Jones said.