Where do the COVID variants come from?

key takeaways

  • To date, WHO has designated five variants of COVID-19 of concern: Alpha, Beta, Gamma, Delta, and Omicron.
  • Experts aren’t sure exactly how these mutations arise, but they suspect that strong mutations may occur in people who have been infected with COVID-19 for a prolonged period of time.
  • Antiviral drugs can help immunocompromised people recover quickly from COVID-19 to reduce mutation accumulation.

Since December 2020, the World Health Organization (WHO) has designated five COVID-19 variants as variants of concern (VOC): Alpha, Beta, Gamma, Delta and Omicron. While experts are keen to track how long these variants last, they’re not sure exactly how new ones emerge.

Because COVID-19 cannot spread without a host, some researchers suspect that new mutations may emerge in people infected with the virus.

Pavitra Roychoudhury, M.S., Lecturer in the Department of Laboratory Medicine and Pathology at the University of Washington, said research suggests that infected immunocompromised individuals may develop mutations because they are at risk for long-term infection.

“In an immunocompromised person, you can have a big divide,” Roy Chaudhry told VigorTip. “Mutations accumulate faster simply because they have been infected for so long and the number of replication cycles is so large compared to the typical infection process.”

A UK study investigated the likelihood of mutations in immunocompromised patients, noting that mutated COVID-19 variants may emerge over the course of “ongoing cases of coronavirus disease.”

Another recent study in France evaluated a 72-year-old man initially infected with the Alpha variant. As the virus replicated, several mutations were found, but these did not evolve into dangerous variants.

Roychoudhury and her team studied mutation accumulation in people with a more typical course of infection. In these studies, viral mutations occurred “at a lower frequency,” but not enough to form new variants.

“During a typical infection, the number of variants that emerge and reach high frequencies is small, but you can have certain mutations that linger at lower frequencies,” she said.

Why a COVID-19 test won’t tell you which variant you may have

Affect the consensus genome

The frequency level of a variant is key in determining its ability to spread to others, or become widespread enough to be flagged as a VOC. For either of the two to occur, the variant would likely need to affect the virus’ shared genome, which can be found in anyone infected with COVID-19.

A consensus genome or consensus sequence is a string of proteins that represent the most common amino acids or nucleotides in a molecule. For example, in the case of COVID-19, a consensus genome containing mostly Delta mutations would be considered Delta variants.

“The consensus genome is like a ‘majority wins’ view of that person,” Roychoudhury said. If one mutation can outperform the original strain, the “beneficial” mutation will eventually be reflected in the patient’s shared genome.

Even if a variant does not reach a high enough frequency to alter the shared genome, it is still possible for a person to transmit the variant to another host, she added.

Scientists predict that there are thousands of viral particles with unique mutations that do not spread far enough to be identified as variants of interest or concern. But the good news is that our immune systems may be evolving to resist mutation.

“Typically, the person’s immune system is also at work trying to clear the virus,” Roy Chaudhry said, adding that the virus doesn’t usually stay in the body long enough to become a new variant.

Antiviral drugs are critical to helping immunocompromised infected individuals fight off COVID-19 quickly to reduce the risk of further mutation accumulation, she added.

what does this mean to you

If you have COVID-19, the virus can replicate and mutate. Most mutations are not sufficient to create entirely new variants. But people who have been infected with the virus for a longer time may develop new variants. In all cases, people should follow masking and isolation protocols while contracting the virus.

The information in this article is current as of the date listed, which means that you may have updated information as you read this article. For the latest updates on COVID-19, visit our Coronavirus news page.