In addition to old age and certain underlying diseases, genetics can influence whether we become severely affected or only suffer mild illness from COVID-19. Previous studies on mainly people of European ancestry have found that individuals carrying a particular segment of DNA have a 20 percent lower risk of developing a critical COVID-19 infection. This DNA segment encodes genes in the immune system and is inherited from Neanderthals in about half of all people outside Africa.
This region of DNA is, however, packed with numerous genetic variants, which makes it challenging to disentangle the exact protective variant that could potentially serve as a target for medical treatment against severe COVID-19 infection.
Studied people of different ancestries
To identify this specific gene variant, researchers in the current study looked for individuals carrying only parts of this DNA segment. Since the Neandertal inheritance occurred after the ancient migration out of Africa, the researchers saw a potential in focusing on individuals with African ancestry who lack heritage from the Neanderthals and therefore also the majority of this DNA segment. A small piece of this DNA region is, however, the same in both people of African and European ancestries.