Relatively Stable SARS-CoV-2 Genome Is Good News For A Vaccine

The genome of the novel coronavirus SARS-CoV-2 has remained relatively stable during its global spread, suggesting that a vaccine could confer long-term protection, according to The Washington Post. Although all replicating viruses accumulate some mutations that persist due to natural selection, the genetics of SARS-CoV-2 suggest that it is not mutating at a high rate, researchers report. They tell the Post that the virus’s proofreading machinery reduces both the rate of mutation and the error rate, and that no strains appear to be more dangerous than others.

There exist roughly four to 10 genetic differences between the origin virus from Wuhan and the strains currently circulating in the United States, molecular geneticist Peter Thielen of Johns Hopkins University tells the Post. “That’s a relatively small number of mutations for having passed through a large number of people,” he says. “At this point, the mutation rate of the virus would suggest that the vaccine developed for SARS-CoV-2 would be a single vaccine, rather than a new vaccine every year like the flu vaccine.” Thielen adds that the coronavirus vaccine might bear similarities to the vaccines for the measles or chickenpox, both of which offer long-lasting immunity.

“The virus has not mutated to any significant extent,” virologist Stanley Perlman of the University of Iowa agrees in a comment to the Post.

Benjamin Neuman, a virologist at Texas A&M University-Texarkana, pointed out key differences between the coronavirus and influenza. “Flu does have one trick up its sleeve that coronaviruses do not have—the flu virus genome is broken up into several segments, each of which codes for a gene,” he tells the newspaper. “When two flu viruses are in the same cell, they can swap some segments, potentially creating a new combination instantly—this is how the H1N1 ‘swine’ flu originated.” Neuman points out there is just one “pretty bad strain” of the coronavirus so far, but that if it persists for a year, more diversity may emerge.

According to the Post, scientists claim it’s possible that a small mutation in SARS-CoV-2 could have a large effect on clinical outcomes, though there are currently no signs of this occurring. Experts are now developing a number of vaccines against the novel coronavirus, which may become available within a year to 18 months.

—Amy Schleunes

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