on why some people fell seriously ill and others didn’t

"Scientists at the Mario Negri Institute for Pharmacological Research in Milan spent the past few years analyzing possible links between DNA variations and Covid-19. Their study, published in the journal iScience and based on a sample of nearly 10,000 people in the Bergamo area, identified several genes associated with the development of severe respiratory illness. Three of those genes belonged to a group of variations in DNA, or haplotype, inherited from Neanderthals.

The Italian study found that people who carried the Neanderthal haplotype were twice as likely to develop severe pneumonia from a Covid infection than those who didn’t, and three times as likely to be hospitalized in intensive-care units and put on ventilators.

Unknown is whether the haplotype is more common in the Bergamo region than in other Italian or European regions. Epidemiologists still don’t know why parts of northern Italy suffered such high death tolls, especially early in the pandemic. Scientists have suggested factors could have included age, air pollution and that the virus hit the region early in the pandemic and spread undetected.

“This study shows there is a particular section of the human genome that is significantly associated with the risk of getting Covid-19 and of developing a severe form of it,” says Giuseppe Remuzzi, an infectious-disease expert and director of the Mario Negri Institute, who oversaw the research. “That section is more important than any others to explain why some fall seriously ill.”

In Bergamo, 33% of those who developed life-threatening forms of Covid had the Neanderthal haplotype, Remuzzi said. The haplotype was less present in people who developed mild or no symptoms from a Covid infection. "

https://www.wsj.com/health/wellness/neanderthal-genes-are-linked-to-severe-covid-risk-d992ccad