FACT CHECK: Is a new mutation making the COVID-19 virus more contagious?
MORE EVIDENCE NEEDED. Scientists say the existing research isn’t sufficient to support the theory.
On May 6, news outlets began reporting that a more contagious mutation of the COVID-19 virus was quickly out-competing the version of the virus first found in Wuhan. Sky News, one of the first outlets to pick up the story, reported that the new form of the virus was “sweeping Europe and the US—and could even reinfect those who already have antibodies.” There are, however, doubts throughout the scientific community about whether there is evidence to support these claims.
The story is based on a preliminary study from the Los Alamos National Laboratory (LANL) in the United States. Using an international database called the Global Initiative on Sharing All Influenza Data (GISAID), the research team identified a mutation in the virus’s spike protein, which they argue may have improved its ability to bind to human cells, making the virus more transmissible.
“D614G [the mutation] is increasing in frequency at an alarming rate, indicating a fitness advantage relative to the original Wuhan strain that enables more rapid spread,” the authors wrote. They found that the virus with the mutation spread quickly in Europe and North America, and that it had become the “dominant form” in Canada and the US by the end of March.
However, many scientists are skeptical of the claims laid out in the study. Lisa Gralinski, a University of North Carolina epidemiologist who specializes in coronaviruses, told The Atlantic that the claims are “overblown,” and virologists interviewed by the Los Angeles Times had mixed responses.
It’s important to note that the LANL paper is “pre-print,” meaning it is based on preliminary findings released to the scientific community for comments and discussion before the peer-review process.
To figure out what the study does and does not tell us about COVID-19, we enlisted the help of Robyn Lee, an infectious disease epidemiologist and applied bioinformatician at the University of Toronto’s Dalla Lana School of Public Health.
The new mutation of the virus does not necessarily make it more contagious
There is not sufficient evidence in the study to prove that the identified mutation makes the virus more transmissible, according to Lee. “It's not entirely implausible that this mutation could increase the ability of the virus to infect cells, but with this type of analysis and the data they've used, we actually can't make those kinds of conclusions,” Lee says.
According to the paper, the researchers analyzed genetic data, but they did not conduct experiments to find out how the mutation affects transmission. “Does it actually affect the way the virus can infect the cell? Do we see this in animal studies as well? Does it increase transmission between animals that are infected? These are things that would have to be investigated further to make any sort of claims about transmissibility,” Lee says.
It could be that the new mutation of the virus is more transmissible, but it could also be becoming more prevalent in Europe and the US for other epidemiological reasons, Lee says—including the ways that different nations have responded to the virus. For example, the US implemented travel restrictions on Europe, where the mutation was first detected, much later than it did on China, which could have contributed to the spread of the virus with the mutation.
It’s still unclear whether you can get COVID-19 twice
In the pre-print study, the team of researchers wrote that the mutation could make patients susceptible to a second infection. Lee says this claim should be viewed with skepticism. “Without experimental data that shows that this does, in fact, affect antibody binding and [compares] the virus with the mutation to the one without the mutation, I'm not sure they can make this claim,” she says.
In sum, the claims in the pre-print are not implausible, but the evidence in the study is not sufficient to prove its conclusions. Further research is needed.