According to a new study, genetic tests promising to evaluate a person’s risk of contracting severe Covid-19 provide inconsistent results and are not based on established scientific information.
There have been some preliminary findings that suggest that at a person’s genetic makeup may play some role in determining whether they are at more risk of getting, or having severe outcomes from Covid-19. However, many of these results have yet to be validated on large numbers of people and the laboratory experiments to directly prove whether a particular genetic variant influences Covid-19 infection risk or outcomes have largely not been done. Most of the evidence currently available suggests a correlation between some genetic variants and Covid-19 outcomes, but does not directly show that the variants cause the outcome.
The new research was presented this week at the National Society of Genetic Counselors annual meeting and evaluated 5 commercially available direct-to-consumer genetic tests claiming to determine an individual’s risk of Covid-19 infection or likelihood of developing severe Covid-19 symptoms. The tests were from SelfDecode, Sequencing.com, GeneInformed, LifeDNA, and Xcode and analyze raw genotyping data from companies such as 23andMe. The cost of the Covid-19 suceptibility tests ranged from free to $59, although extra charges to access data were also sometimes present. The researchers found that there was a great deal of variability between tests in the number of genes analyzed and also which genes or variants were tested.
Three of the five tests claimed they could report an individual’s risk of actually being infected with Covid-19. One tested for variants of 4 genes, one for variants in 7 genes and the third tested 31 gene variants. But only one variant was included in all three tests, raising questions about why genetic tests designed to evaluate the same thing were so different by design. The remaining two tests claimed to predict the risk of severe Covid-19 symptoms, but these showed even more variability than the three tests supposedly predicting risk of infection.
“The message for those who want to know their Covid-19 risk is ‘ buyer beware,’” said aid Esther Choi, B.S., coauthor of the study and a genetic counseling student at Kean University Genetic Counseling Graduate Program in Union, New Jersey. “Many direct-to-consumer genomic tests are not regulated , so they often fly under the radar of the medical community and the Covid-19 information they provide may be misleading and give consumers a false sense of security,” added Choi.
The researchers then evaluated the different tests using genetic data from one individual, expecting to see similar results. However, one test said the person had lower than average risk of severe Covid-19, while another test said the same person had higher risk for severe Covid-19 symptoms. Even with regard to specific genetic variants, the tests did not always agree on what the implications of these were. For example, a particular variant in a gene called IL-18 was described as both an increased chance for Covid-19 severity and a moderately reduced risk of Covid-19 complications, depending on the test.
So what should people wanting to evaluate their risk for Covid-19 do?
“They’re better off avoiding these tests and instead should consult medical professionals,” said Choi.