For the study, which was published on the preprint server MedRxiv, meaning it has yet to be peer-reviewed, researchers sequenced the genomes of 5,085 strains of SARS-CoV-2 in Houston, Texas. (A genome is an organism’s complete set of DNA.) The virus was recovered during an initial wave of infections in Houston, and again during its “ongoing massive second wave of infections,” the study authors wrote.
There were several different strains of the virus that showed up in Houston initially, but when an outbreak happened over the summer, the researchers discovered that nearly every genetic sample they took contained a mutation on the surface of the virus. That mutation altered the structure of the spike protein that gives the virus its crown-like appearance, which the researchers say is linked to “increased transmission and infectivity.”
People who were infected with these mutated strains also had higher viral loads in the back of their nose and throat when they were originally diagnosed, the study found, suggesting that the new strains were more contagious.
“There is no evidence that you are more likely to have a bad outcome by that variant, but it seems very clear from a variety of lines of evidence that it is better able to spread,” says study co-author James Musser, M.D., Ph.D., chair of the Department of Pathology & Genomic Medicine at Houston Methodist.
Should you be concerned about these novel coronavirus mutations?
This is “certainly” concerning news, according to William Schaffner, M.D., an infectious disease specialist and professor at the Vanderbilt University School of Medicine. “Here we have a contagious virus that’s become even more contagious,” he says.
The change in the spike protein “has made it such that it can attach more readily to the cells in the back of the throat,” Dr. Schaffner explains. As a result, “the virus can get into those cells more readily and multiply more. Any time you enhance the multiplication of the virus, you expect that person will shed more virus and thus become more contagious.”
That said, mutations are expected, and this news shouldn’t make you panic just yet. “Mutations of different sources are common among certain viruses,” Dr. Schaffner says. “We had anticipated that this coronavirus might change.”
One expert theorizes that this could be the virus’s way of “responding” to measures that prevent transmission, such as mask-wearing and social distancing, per The Washington Post.
Discovering mutations can be useful from a scientific standpoint because “they allow us to track spread and exposures,” says John Sellick, D.O., an infectious disease expert and professor of medicine at the University at Buffalo/SUNY. “This particular mutation originated in Europe and “allowed us to determine that most of the East Coast virus came from Europe.”
There were many factors that drove spikes in COVID-19 cases in the summer, Dr. Schaffner says, adding that “this may have been a contributor.”
Will these mutations impact the development of a COVID-19 vaccine?
It doesn’t appear to be the case, Dr. Schaffner says. The basic structure of the virus has “remained pretty stable so far,” which allows people to develop immunity after contracting COVID-19 and for vaccine development to move forward, he says.
But if mutations continue to develop and become the norm, it could alter the way we approach the vaccine year-to-year, similar to the flu shot. Influenza has several different strains that circulate during any given year, so the vaccine is adjusted accordingly.
That’s why it’s so important to identify mutations now. “We need to be studying what [these various mutations] mean from a functional standpoint, we need to be aware that they are occurring, and we need to keep our eye on them at this point,” Dr. Musser says.
What can you do to protect yourself and others?
The same COVID-19 safety guidelines still apply, Dr. Musser says. As a refresher, the Centers for Disease Control and Prevention (CDC) recommends doing the following:
- Wash your hands often with soap and water for at least 20 seconds.
- Avoid close contact with people who are not in your household.
- Keep a six-foot distance from others when possible.
- Cover your mouth and nose with a mask when you’re in public.
- Cover coughs and sneezes.
- Stay home if you feel sick.
- Regularly clean and disinfect frequently touched surfaces.
The findings of this new study haven’t changed anything when it comes to keeping yourself and others safe from COVID-19, but Dr. Schaffner says they are “all the more reason to wear a mask and practice social distancing.”
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