Scientists started looking for information on what, if any, factors made people more or less likely to contract SARS-CoV-2 and more or less likely to become very ill if they did, shortly after the virus started to spread over the world.
The American Society of Haematology reports two research published in the journal “Blood Advances” in 2020 reveal that people with type O blood may have a lower chance of Covid-19 infection and a decreased likelihood of severe consequences, including organ problems, if they do get sick.
The biomedical research community is rapidly trying to pinpoint coronavirus risk factors and potential treatment targets in the wake of the pandemic.
These new studies provide more proof that blood type and Covid-19 vulnerability may be related, but more research is needed to understand why and what it means for patients.
Early research from China, according to “Time Magazine”, revealed that people with certain blood types, specifically blood type A, may be more susceptible to illness, while people with type O may be more resistant to it.
Public health professionals are unsure of the significance of blood type as a potential risk factor for Covid-19 because some small studies that looked at the correlations found them, while others did not.
Dr Sean Stowell, an associate professor of pathology at Brigham and Women's Hospital and Harvard Medical School, discovered that the finger-like projections jutting from the SARS-CoV-2 virus were very similar to those from blood groups on human cells.
He was working with researchers at the US Centres for Disease Control and Prevention to develop a blood-based test for Covid-19, according to the National Institutes of Health.
This similarity is significant because the virus uses those protein projections as an access point to attach to and infect human cells.
If the virus is able to identify the blood group proteins, then it's possible that some blood types could increase the virus's capacity to infect cells.
The retrospective investigation suggests that blood type O may offer some protection against Covid-19 infection.
Researchers compared data from a control group of more than 2.2 million people to data from more than 473 000 people tested for Covid-19 in the Danish health registry.
According to Everyday Health, they discovered that there were fewer people with blood type O and more people with blood types A, B, and AB among those who tested positive for Covid-19.
According to the study's findings, Covid-19 infection may be more common in blood types A, B, or AB than in blood type O. The rate of infection between the A, B, and AB types was not significantly different, according to the researchers.
The researchers additionally adjusted for ethnicity and maintained that fewer persons with blood type O tested positive for the virus because blood group distributions differ among ethnic communities.
According to a separate retrospective study, the American Society of Haematology reported that people with blood groups A or AB seem to have a more severe Covid-19 disease than people with blood groups O or B.
The researchers analysed data on 95 critically ill Covid-19 patients admitted to hospital in Vancouver, Canada. They discovered that those with blood types A or AB were more likely to need mechanical breathing aids, indicating that these blood types had higher rates of Covid-19 lung injury.
They also found that more patients with blood types A and AB needed dialysis for kidney failure.
According to the researchers, the results indicated that patients with those two blood groups could be more susceptible than those with blood types O or B to organ malfunction or failure brought on by Covid-19.
In addition, although those with blood types A and AB did not spend more time in the hospital overall than those with types O or B, they did spend more time on average in the intensive care unit (ICU), which could indicate a higher Covid-19 severity level, said Dr Mypinder Sekhon, of the University of British Columbia.
The new knowledge about how Covid-19 risk may be influenced by blood types may help clinicians better control risk in populations such as the elderly and those with weakened immune systems.
Does that imply that those with type A blood should exercise extra caution to avoid exposure and that they have a higher chance of contracting a more serious illness? Potentially, but it's not a given, according to the study’s authors.
This is due to the fact that blood type is one of many factors that affects both the chance of contracting Covid-19 and the likelihood of suffering serious consequences.
Although some studies have shown that having type A blood is associated with a 48% higher risk of dying from Covid-19, not all people with type A blood have the same levels of A group antigens in their cells, according to Healthline.
The study's authors intend to build on this research and investigate how Covid-19 risk differs between those with type B blood, whose antigens are hardly different from those of type A.
They are currently carrying out research to determine why the virus doesn't connect to type B quite as well as it does to type A.
No matter what blood type you are, you should continue to follow the recommended precautions, such as getting vaccinated and wearing a mask when diseases start to spread.