[...] SARS-CoV-2, the virus that causes COVID-19, impacts people in different ways after infection. Some experience only mild or no symptoms at all while others become sick enough to require hospitalization and may develop respiratory failure and die.
Now, researchers at the Okinawa Institute of Science and Technology Graduate University (OIST) in Japan and the Max Planck Institute for Evolutionary Anthropology in Germany have found that a group of genes that reduces the risk of a person becoming seriously ill with COVID-19 by around 20% is inherited from Neanderthals.
[...] Last year, Professor Svante Pääbo and his colleague Professor Hugo Zeberg reported in Nature [scitechdaily.com] that the greatest genetic risk factor so far identified, doubling the risk to develop severe COVID-19 when infected by the virus, had been inherited from Neanderthals.
Their latest research builds on a new study, published in December last year from the Genetics of Mortality in Critical Care (GenOMICC) consortium in the UK, which [...] pinpointed additional genetic regions on four chromosomes that impact how individuals respond to the virus.
Now, in a study published recently in Proceedings of the National Academy of Sciences (PNAS), Professor Pääbo and Professor Zeberg show that one of the newly identified regions carries a variant that is almost identical to those found in three Neanderthals – a ~50,000-year-old Neanderthal from Croatia, and two Neanderthals, one around 70,000 years old and the other around 120,000 years old, from Southern Siberia.
[...] To try to understand how this variant affects COVID-19 outcomes, the research team took a closer look at the genes located in this region. They found that three genes in this region, called OAS, code for enzymes that are produced upon viral infection and in turn activate other enzymes that degrade viral genomes in infected cells.
“It seems that the enzymes encoded by the Neanderthal variant are more efficient, reducing the chance of severe consequences to SARS-CoV-2 infections,” Professor Pääbo explained.
[...] They found that the variant increased in frequency after the last Ice Age and then increased in frequency again during the past millennium. As a result, today it occurs in about half of people living outside Africa and in around 30% of people in Japan. In contrast, the researchers previously found that the major risk variant inherited from Neanderthals is almost absent in Japan.
“The rise in the frequency of this protective Neanderthal variant suggests that it may have been beneficial also in the past, maybe during other disease outbreaks caused by RNA viruses,” said Professor Pääbo.
Obligatory, see also: Ozzy Osbourne's Genome Reveals Some Neandertal Lineage [scientificamerican.com].
 Hugo Zeberg, Svante Pääbo. The major genetic risk factor for severe COVID-19 is inherited from Neanderthals [open], Nature (DOI: 10.1038/s41586-020-2818-3 [doi.org])
 Hugo Zeberg, Svante Pääbo. A genomic region associated with protection against severe COVID-19 is inherited from Neandertals [open], Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.2026309118 [doi.org])