Neanderthal genes may be cause of higher risk of Covid

NEANDERTHAL genes that protected people from smallpox could be the reason that some ethnic groups are more at risk from Covid, a study suggests.

Throughout the pandemic, South Asians have been at greater risk of severe Covid, even when accounting for factors such as deprivation, jobs and living conditions. Dr Hugo Zeberg, of the Max Planck Institute for Evolutionary Anthropology in Germany, showed that mutated genes inherited from Neanderthals doubled severe Covid risk.

Around half of South Asians carry the mutations, compared with a fifth of Europeans, but Dr Zeberg realised the variants must have been beneficial at one time, in order for them to be passed on. In his research, he found that they lower the risk of HIV by about 27 per cent, which suggests that they would also prevent other diseases that enter cells in the same way, such as smallpox.

“This major genetic risk factor for Covid-19 is so common that I started wondering whether it might actually be good for something,” he said. “We don’t know at the moment why it was likely advantageous 10,000 years ago. There are many genes involved in the immune system in this region of the genome, so there are many plausible candidate genes. If I were to guess, smallpox would be a good candidate. It also enters cells using chemokine receptors.”

Some people become seriously ill when infected with Covid while others have mild or no symptoms. In addition to known risk factors such as advanced age and other illnesses such as diabetes, genes contribute to the chances of ending up with a severe infection.

People with the Neanderthal mutation on chromosome 3 have fewer CCR5 receptors, which HIV uses to enter human cells, the same entry method as smallpox, so researchers believe the mutation may have happened thousands of years ago to protect against the virus, which has since been eradicated. The research was published in