- Neanderthals were a different species of archaic human who lived in Europe and Asia. They became extinct around 40,000 years ago, although 2% of the DNA of people living in Europe and Asia derives from Neanderthals.
- Previous research discovered that if a person has a specific Neanderthal gene, they have a higher risk of experiencing severe COVID-19 symptoms.
- In a new study, researchers found another Neanderthal gene with the opposite effect, which may offer protection against severe COVID-19.
- Half of all people outside of Africa possess this protective gene, which reduces their need for intensive care for COVID-19 by 20%.
Researchers worldwide have worked tirelessly to uncover how SARS-CoV-2 interacts with the body and why some people with COVID-19 remain virtually unaffected while others have severe, life threatening symptoms.
The Centers for Disease Control and Prevention (CDC) COVID-19 guidance indicates that early in the pandemic, data from a Chinese study of over 44,000 people with the condition showed the disease ranged in severity from mild to critical.
Of these people, researchers found:
- 81% had mild to moderate symptoms
- 14% presented with severe symptoms
- 5% experienced critical illness
Factors that increase the risk of severe disease became apparent soon after the pandemic began.
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Besides advanced age, other risk factors for severe COVID-19 include underlying health conditions, including cancer, type 2 diabetes, and heart disease. However, these factors fail to explain why some individuals with COVID-19 hardly notice a symptom, while others end up in the hospital critical care unit with severe illness.
Genes may help explain this phenomenon.
A study published last year in the New England Journal of Medicine identified two gene regions associated with severe COVID-19 — one located on chromosome 3, which contains six genes, and the other on chromosome 9 that determines ABO blood groups.
Gene variant linked to severe COVID-19
A September 2020 study that appears in the journal Nature presented more evidence that genes may play a role in the severity of COVID-19.
In the research, the scientists found a Neanderthal gene variant on chromosome 3 that significantly increased the risk for severe COVID-19 symptoms. They found having this variant meant there was a 60% increased likelihood of being hospitalized.
Scientists have found the variant in 16% of people from Europe and 50% of people from South Asia. Neanderthal variants are rare in Africa.
In particular, the researchers found this variant in 63% of people from Bangladesh, who have double the risk of dyingfrom COVID-19, compared with white people in the United Kingdom.
The research was led by Hugo Zeberg and Svante Pääbo, scientists at Karolinska Institute in Sweden and the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
Neanderthal gene offers protection
The latest study from the same team of scientists found another Neanderthal gene with the opposite effect. Their findings appear in the journal PNAS.
Using data from the Genetics of Mortality in Critical Care consortium, the team found a genome type on the OAS1 region of chromosome 12 that appears to protect against severe COVID-19.
The researchers say the presence of each copy of OAS1 reduces the need for intensive care by around 22%.
Genes located in this region encode proteins that activate enzymes critical in the body’s immune response to RNA viruses. These enzymes help break down viral genomes.
The study also indicates that this Neanderthal-inherited gene’s prevalence has increased since the last Ice Age. Scientists believe it is present in approximately half of all people outside Africa.
Neanderthal gene origins
Genome sequencing by The National Institutes of Health (NIH) through the National Genome Research Institute helps explain the Neanderthal gene variant’s origins.
In the news report, Complete Neanderthal Genome Sequenced, researchers explain:
“Humans migrating out of Africa were likely to be small pioneering groups and appear to have encountered Neanderthals living in the Fertile Crescent of the Middle East about 60,000 years ago. As modern humans migrated out of the Middle East after encountering Neanderthals and dispersed across the globe, they carried Neanderthal DNA with them.”
The research team concluded in present-day humans, 2% of the genome comes from Neanderthals.
COVID-19 treatments
In a medRXiv analysis of the latest Neanderthal gene study, authors say further research could outline potential gene treatments for COVID-19.
For instance, the authors suggest investigating existing drugs that might influence these genes.
They write, “Available medicines, such as phosphodiesterase-12 inhibitors, increase OAS1 and could be explored for their effect on COVID-19 susceptibility and severity.”
Developing a greater understanding of genetic susceptibilities to COVID-19 can inform policy by helping identify at-risk populations who need additional support to avoid SARS-CoV-2 infection.
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