The risk factors for COVID-19 are many: old age; obesity; heart conditions. But early genetic studies have identified another trait that some people who develop severe COVID-19 seem to share: a cluster of genetic variations on their third chromosome.
And that DNA sequence likely derives from Neanderthals, says Hugo Zeberg of the Max Planck Institute. “It’s quite striking this variant has lingered on for 50,000 years.”
Fifty-thousand years ago is the approximate time humans and Neanderthals interbred. And over the millennia, these Neanderthal variants have become more common in some Homo sapiens populations than others.
For example, 16 percent of people of European descent carry at least one copy of the Neanderthal stretch; half of South Asians do—and nearly TWO-thirds of Bangladeshis.
“And it’s fascinating it is so high. Points to the fact that it must have been beneficial in the past. It’s much higher than we expect. And then it’s totally expunged in East Asia and China. So something has happened, driving the frequency up in certain places, and removing it totally in other places.”
The details are in the journal Nature. [Zeberg, H. et al. The major genetic risk factor for severe COVID- 19 is inherited from Neanderthals]
Zeberg and his colleague write that perhaps the Neanderthal DNA happens to boost the risk of developing severe COVID-19—and they point to the fact that in the U.K., people of Bangladeshi descent have twice the risk of dying of COVID-19 than the general population.
But as epidemiologist Keith Neal of the University of Nottingham pointed out via email, people of African descent in the U.K. are also being hurt more by the virus—despite having hardly any Neanderthal genes.
Instead, it’s social factors—like crowded, multigenerational households or working front line jobs—that are more likely to be driving the trends seen in the U.K. That’s according to Andrew Hayward, director of the Institute of Epidemiology and Health Care at University College London.
And, as both epidemiologists pointed out—it’s worth remembering that you can only develop severe COVID-19 if you’re exposed to the virus in the first place.
[The above text is a transcript of this podcast.]