People with blood type A may be at greater risk from coronavirus, scientists have claimed.

Researchers in China looked at blood group patterns of more than 2000 people who had been diagnosed with the virus and treated in hospital.

They found that those with blood type A were more vulnerable to infection and tended to develop more severe symptoms, while those with blood type O had a "significantly lower risk" of getting the disease.

Although the study is yet to be peer-reviewed, the researchers are urging medical professionals and governments to consider blood types when assessing how at risk a patient may be.

Gao Yingdai, a researcher at the State Key Laboratory of Experimental Haematology in Tianjin, said: "If you are type A, there is no need to panic. It does not mean you will be infected 100 per cent.

"If you are type O, it does not mean you are absolutely safe, either. You still need to wash your hands and follow the guidelines issued by authorities."

The researchers, led by Dr Wang Xinghuan of the Zhongnan Hospital at Wuhan University, looked at the blood of 2173 people who had been diagnosed with coronavirus.

While 32 per cent of the Chinese population had type A blood, the percentage of infected patients of that type was 41. And while 34 per cent of the population had type O, just 25 per cent of those in hospital were of that type.

Of the 206 patients in the study who died, 85 had blood type A, equivalent to 41 per cent of all deaths.

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Human blood is grouped into four types: A, B, AB, and O. Each letter refers to a kind of antigen, or protein, on the surface of the red blood cells that transport oxygen around the body. For example, the surface of red blood cells in type A has A-antigens.

Blood type is known to affect health. People with type O blood are at a higher risk of uncontrolled bleeding after an accident, possibly because it contains fewer blood clotting factors.

Conversely, some researchers believe that those with types A, B and AB blood have an increased risk of coronary heart disease, due to increased levels of inflammatory markers and certain proteins in the blood that lead to blood-clotting.

People have also been found to be more susceptible to different strains of norovirus depending on blood type, while those with types A and AB are less likely to develop an adequate immune response to influenza.

Prof Robin May of the School of Biosciences at the University of Birmingham, said it was unclear why a person with blood type A might be more susceptible to coronavirus.

Because it infected the lungs, it was "harder to see how a virus that does not live in red blood cells would be impacted by your blood type", he added.

The results should not be a cause for concern for those with A type blood, as "the proportion of increased risk associated with the blood group is quite slender" when compared with "the proportion of relative risk of washing your hands", he said.

In the UK population, 48 per cent have type O blood – the most common group – while 38 per cent have type A.