Did you survive Covid? Maybe you can thank your Neanderthal ancestors - CNN

It was found in all the samples they took of Neanderthal DNA, and in about 30% of samples from people of European and Asian origin.

The genetic region involved affects the body's immune response to RNA viruses such as the coronavirus, as well as West Nile virus and hepatitis C virus, the researchers reported Tuesday in the Proceedings of the National Academy of Sciences.

"This region encodes proteins that activate enzymes that are important during infections with RNA viruses," they wrote.

It may be one of those mutations that has been passed down over the millennia because it helped people survive, Svante Paabo and Hugo Zeberg of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany reported.

"We show that a haplotype on chromosome 12, which is associated with about a 22% reduction in relative risk of becoming severely ill with COVID-19 when infected by SARS-CoV-2, is inherited from Neandertals," they wrote.

"The relative risk of needing intensive care is reduced by about 22% per copy of the Neandertal haplotype," they added.

"This haplotype is present at substantial frequencies in all regions of the world outside Africa," they added.

"It is present in populations in Eurasia and the Americas at carrier frequencies that often reach and exceed 50%."

The finding could help explain why Black patients are so much more likely to suffer severe coronavirus disease.