Study found people with blood type A at higher risk of Covid-19 – but results preliminary, no peer review yet
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“People with blood type A may be more vulnerable to coronavirus, China study finds,” reads the headline of an 18 March 2020 article in Malaysian newspaper the Star.
The article says medical researchers in China compared the blood patterns of more than 2,000 coronavirus-infected patients in the cities of Wuhan and Shenzhen with the blood patterns of healthy people. They found that people with blood type A showed a higher rate of infection and more severe symptoms while those with blood type O had a lower risk of infection.
The article claims the researchers suggested introducing ABO blood typing in both patients and medical professionals as a routine part of Covid-19 management. It adds that people with blood type A may need better personal protection against the virus, more vigilant surveillance and more aggressive treatment.
The claim has also been reported in the South China Morning Post, the Independent and the Telegraph.
Blood types and new coronavirus
Blood is made up of red blood cells, white blood cells and platelets found in plasma. There are four main blood groups, which are genetically inherited and determined by the levels of antibodies and antigens found in blood. The blood groups are type A, type B, type O and type AB.
Coronaviruses are a group of viruses that cause mild to serious diseases, from the common cold to severe acute respiratory syndrome.
In December 2019 a new strain of coronavirus was found to be responsible for an outbreak of Covid-19 in Wuhan, China. There have so far been more than 220,000 confirmed cases of Covid-19 worldwide and nearly 9,000 deaths. More than 84,000 people have recovered.
Preliminary results in study need further testing
The study, Relationship between the ABO Blood Group and the COVID-19 Susceptibility, was published on 11 March. It was carried out at the Zhongnan Hospital of Wuhan University by a team of researchers who analysed the blood group distribution in 2,173 patients tested positive for Covid-19.
They compared the blood types of patients from three different hospitals in Wuhan and Shenzhen to the blood types of a sample size of 26,980 healthy people from the two cities.
The researchers found that of the 3,694 healthy people sampled in Wuhan, 32.16% of them were blood type A, while 37.75% of Covid-19 patients had the same blood type, showing a higher risk of infection for blood type A. While 33.84% of the healthy population was blood type O, only 25,8% of the infected people had blood type O.
“People with blood group A have a significantly higher risk for acquiring Covid-19 compared with non-A blood groups, whereas blood group O has a significantly lower risk for the infection compared with non-O blood groups,” the researchers conclude.
Of 206 patients who had died from Covid-19, 41.26% of them were found to be blood type A while only 25.24% of them were blood type O. This suggested that people with blood type A are more likely to have more severe symptoms, including death.
The researchers found the results consistent with the samples in Shenzhen and across different age and gender groups.
The researchers do recommend blood typing be included in Covid-19 treatment plans. They also say the results are preliminary and need further testing.
“It should be emphasised that due to the imitations discussed above, one should be cautious to use this study to guide clinical practice at this time. This study encourages further studies,” they say.
The study has not yet been peer-reviewed. So it should be viewed with caution and not taken as definitive proof that people with blood type A are more at risk.