Blood type and DNA difference could increase risk of severe Covid, research finds

Differences in DNA could explain why some people are more seriously ill from Covid, researchers have found.

A new study, published in the Nature Journal, identified 16 new genetic variants - differences in DNA - associated with severe coronavirus, including some related to blood clotting, immune response and inflammation.

One genetic variant was found to be slower at signalling to the immune system that cells are under attack from the virus.

Having just one of the 16 genes could be the difference between getting a mild cough or being admitted to intensive care, according to researchers.

What did researchers find?

The government-funded study, which is the largest of its kind, saw researchers from the GenOMICC consortium, led by experts at the University of Edinburgh, assess the genes of more than 57,000 people across the UK, including 7,941 Covid patients from 224 intensive care units.

Researchers from the GenOMICC consortium – a global collaboration to study genetics in critical illness – led by University of Edinburgh in partnership with Genomics England, assessed the genes of more than 57,000 people across the UK.

They sequencing the genomes of 7,491 patients from 224 intensive care units and compared their DNA with 48,400 other people who had not had coronavirus, and 1,630 people who had experienced mild Covid.

Key differences in 16 genes were found among intensive care patients.

The findings included how a single gene variant was enough to increase a patient’s risk of severe disease.

One gene variant, called interferon alpha-10, was found to be less effective in signalling to the body’s immune system that cells were under attack from a virus and people with this gene were more likely to die from Covid.

Another variant, called Factor 8, is linked to the blood clotting disorder haemophilia and was also found in severely ill patients.

Experts say the findings could help to reveal a person’s risk from various diseases, such as Covid, and suggest a specific treatment may help manage disease in the early stages.

Professor Kenneth Baillie, the project’s chief investigator and a consultant in critical care medicine at University of Edinburgh, said: “These results explain why some people develop life-threatening Covid-19, while others get no symptoms at all.

“But more importantly, this gives us a deep understanding of the process of disease and is a big step forward in finding more effective treatments.

“It is now true to say that we understand the mechanisms of Covid better than the other syndromes we treat in intensive care in normal times – sepsis, flu, and other forms of critical illness.

“Covid-19 is showing us the way to tackle those problems in the future.”

Researchers say that not everyone will have all of the DNA changes they identified, meaning some people will have a greater or lesser tendency to have severe outcomes.

Professor Sir Mark Caulfield from Queen Mary University of London, formerly chief scientist at Genomics England and co-author on the study, explained: “Through our whole genome sequencing research, we’ve discovered novel gene variants that predispose people to severe illness – which now offer a route to new tests and treatments, to help protect the public and the NHS from this virus.

“I think what we can say today is that these variants do denote people that are more likely to have a critical illness.

“And if we knew about them earlier in the course of their illness, we might be able to consider early intervention with some of the medicines we’ve been talking about, such as dexamethasone or others to try and prevent an adverse outcome.”

Can blood type influence the risk of severe Covid?

Another study, published in The Conversation, suggests that proteins in the blood could be another biological factor that increases the risk of suffering severe disease from Covid.

Some proteins help the body to defend against viruses, while others transport molecules around the body and distribute information.

The study claims that through these functions, blood proteins can impact the severity of coronavirus.

As everyone has different amounts of these proteins in their body, this could explain why some people only develop a runny nose from Covid, while others require intensive care, and in the severest cases, some may die.

Researchers from King’s College London and the Medical University of Vienna assessed more than 3,000 blood proteins using a technique called Mendelian randomisation, which looks at variation in genes and its influence on disease outcomes.

Findings revealed several proteins that potentially increase or decrease the risk of severe Covid.

Increased levels of one protein, called FAAH2, was found to heighten the risk of someone needing hospital treatment for coronavirus, as it causes cells to absorb and inactivate substances called endocannabinoids, which have anti-inflammatory effects.

Having more of these proteins that remove them could be problematic as it potentially lessens the body’s ability to control inflammation caused by Covid.

Another protein identified was the ABO enzyme, which determines your blood group.

The study found that having higher levels of this enzyme appears to increase the risk of hospitalisation from Covid and subsequently needing intensive care.

Previous studies have shown that blood group A is more common in those with severe Covid and this study strengthens the case that the ABO enzyme and blood type influence coronavirus severity.

It was also found that Covid can cause disease in the blood vessels, especially when severe, but proteins that attract white blood cells to the wall of blood vessels can help to protect against this and help fight off infection.

Researchers said: “Identifying these risk factors may help scientists develop new treatments, as these proteins could be targeted by new medicines - or existing ones that have been repurposed.

“It has also allowed us to draw up a list of proteins that can be prioritised by other researchers, so that in future we can understand even more about what the biological risk factors for Covid are.”

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