It’s estimated that at least 1 in 5 people with a SARS-CoV-2 infection never develop symptoms. Genetics might explain some of these asymptomatic cases, it turns out. In a new study appearing in Nature, people with a particular gene variant appeared to have preexisting T cell immunity to the virus, likely a holdover from previous bouts of the common cold. [JAMA Network]

Why This Is Important

Hollenbach and her coauthors note that many studies have looked at genetic factors in severe COVID-19 disease, but fewer have examined the underpinnings of asymptomatic or mild infection. Insight into factors that allow the immune system to quickly clear the virus could help scientists better understand the disease and improve immunotherapies and vaccines, they say.

Benjamin Solomon, MD, who was not involved with the work, is clinical director of the National Human Genome Research Institute, part of the US National Institutes of Health. “It’s interesting to see a major study focus on people on the less-affected end of the curve, as this can be clinically important and offer useful biological insights, but may be less studied than the other end of the curve,” Solomon wrote in an email.

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