Blood Group O less Likely to contract Corona viruse than any other Blood group | Facts Update
Recent studies reveal that people with blood group O are at lower risk of contracting the novel coronavirus or Covid-19 infection. One study identified ABO blood group as a risk factor for Covid-19, while another said that patients with blood group A or AB are at increased risk for requiring mechanical ventilation
Blood group O less likely to contract coronavirus infection than any other blood type | Study (Image for representation: Reuters)
Even as scientists are working around the clock to identify the Covid-19 risk factors, two new studies, that investigated the "potential role of blood type in predicting" the risk, revealed that people with blood group 'O' are less vulnerable to the novel coronavirus infection than any other blood type.
Two recent studies published in Blood Advances show that people with blood group O are at lower risk of contracting the Covid-19 or SARS-CoV-2 infection.
Although these new studies provide evidence of a potential link between blood type and vulnerability to Covid-19, additional research is needed to better understand why and what it means for patients, a report in Science daily said.
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BLOOD GROUP O LESS VULNERABLE TO COVID-19 | STUDY 1
"Blood group O is associated with a decreased risk for contracting SARS-CoV-2 [Covid-19] infection,"revealed one of the studies.
Researchers found that among the individuals who tested positive for the novel coronavirus, "considerably fewer group O individuals were found", while "conversely, more A, B, and AB individuals were noted".
"This study identifies ABO blood group as a risk factor for SARS-CoV-2 infection but not for hospitalisation or death from Covid-19," the study further said.
This means that that person with blood types A, B, or AB may be at a higher risk of getting infected with Covid-19 than people with type O.
However, the researchers didn't find any significant difference in the rate of infection between A, B, and AB types.
During the course of the study, from February 27, 2020, to July 30, 2020, 841,327 individuals were tested by "real-time polymerase chain reaction" for Covid-19 infection in Denmark. Of these, 473,654 individuals were eligible for the test (7,422 positive and 466,232 negative).
Moreover, a reference group (control group) with relevant blood group information from 2,204,742 non-tested individuals was included.
Torben Barington, MD, of Odense University Hospital and the University of Southern Denmark, and study co-author, was quoted by Science Daily as saying: "It is very important to consider the proper control group because blood type prevalence may vary considerably in different ethnic groups and different countries."
"We have the advantage of a strong control group -- Denmark is a small, ethnically homogenous country with a public health system and a central registry for lab data -- so our control is population-based, giving our findings a strong foundation," he was quoted as saying.
The study said that there was a "slight, but statistically significant, the difference in blood group distribution between the SARS-CoV-2- [negative] individuals and the reference population".
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BLOOD GROUP A, AB: HIGHER RISK OF SEVERITY | STUDY 2
Another recent study revealed that critically-ill Covid-19 patients with blood group A or AB are at a higher risk for requiring mechanical ventilation, CRRT, and prolonged stay at ICU -- suggesting that they had greater rates of lung injury from Covid-19 -- as compared with patients with blood groups O or B.
"Covid-19 patients with blood group A or AB are at increased risk for requiring mechanical ventilation vs those with blood group O or B," the retrospective analysis showed.
"Covid-19 patients with blood groupA or AB appear to exhibit a greater disease severity than patients with blood group O or B," it further said.
Explaining the finding of the study, the Science daily report said: "Blood groups A and AB associated with increased risk of severe clinical outcomes of Covid-19 infection. People with blood groups A or AB appear to exhibit greater Covid-19 disease severity than people with blood groups O or B."
This means, people with blood group O, are unlikely to have severe clinical outcomes.
"Further research is required to delineate the biological mechanisms underpinning these findings," it said.
Mypinder S Sekhon, MD, of the University of British Columbia, and study author was quoted as saying: "The unique part of our study is our focus on the severity effect of blood type on Covid-19. We observed this lung and kidney damage, and in future studies, we will want to tease out the effect of blood group and Covid-19 on other vital organs."
For this study, researchers examined data from 95 critically-ill Covid-19 patients hospitalized in Vancouver, Canada. However, it had several limitations.
These two studies suggest that patients in the two blood groups -- A and AB -- may have an increased risk of organ dysfunction or failure due to Covid-19 than people with blood types O or B, the report in Science Daily concluded.
WHAT PREVIOUS STUDIES SAY
A study published in April 2020 and revised in September said that the "unadjusted prevalence of initial infection" was higher among A and B blood types and lower among AB types, compared with type O".
It also found that Blood type A was at lower risk of both "intubation and death relative to type O, while type AB was at increased risk of both outcomes".
"We found that type B individual were at higher risk of intubation but at lower risk of death, compared with type O," the study said.
The risk of death was slightly increased among type AB individuals and was decreased among types A, B, and Rh-negative types, it revealed.
Another study said: "Patients with blood types B and AB who received a test were more likely to test positive and blood type O was less likely to test positive. Rh+ patients were more likely to test positive."
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WHAT ARE THE BENEFITS OF HAVING BLOOD GROUP O
People with blood type O negative are universal donors -- they can donate their blood to all groups. However, they can only receive O negative blood.
People with blood group O positive can donate blood only to people with positive blood groups -- A+, B+, O+, AB+. They can only receive transfusions from O positive or O negative blood types.
Some reports suggest that people with blood type O are at lower risk of having heart diseases.
Previous studies have shown that "gastric cancer was less common in patients with blood group O".
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