Persons having 'A' blood group more vulnerable to Coronavirus!

The first case of someone in China suffering from Covid-19, the disease caused by the novel coronavirus, can be traced back to November 17, 2019. So, more than a year has passed but Corona pandemic has not stopped yet. Again, scientists are amazed at the way the Coronavirus is causing different symptoms in different people.Some people with Coronavirus may worsen their health conditions very quickly, some people may have very mild symptoms. In some cases, a person seems to be corona positive, but no symptoms are seen.

So, the question comes up again and again - who has the highest risk of getting Coronavirus?
Previous studies have shown several factors - including age, sex and comorbidities, such as cardiovascular disease - are associated with COVID-19 infection. However, severe cases are not limited to these risk groups. Scientists at first thought age was the dominant factor, with young people avoiding the worst outcomes of Covid-19 but new research has revealed a suite of features impacting disease severity.

The global biomedical research community is continually working to identify coronavirus risk factors and potential therapeutic targets. Researchers have already identified certain things that make some people more vulnerable to Covid-19 than others. Men are at greater risk than women. Older people are at greater risk than younger people. Those with chronic health problems like Type 2 diabetes, obesity and serious heart conditions are faring worse than those without them. Black and Latino Americans are at greater risk than Asian Americans and whites. Now there's evidence that blood type/group could be a risk factor too for Coronavirus.

Various research studies including some latest one suggests that that people's blood type/group might be an important risk factor - both for being infected by the Coronavirus and for falling dangerously ill. Studying a no. of patients with Coronavirus, scientists revealed that persons with Type 'A' blood are more likely to have severe Corona disease while those with Type 'O' are less likely. That means your blood type/group may make you more susceptible to catching coronavirus, though additional research is needed to better understand why and what it means for patients.
Results of research on COVID-19 risks by blood groups:

In a recent research report, Canadian scientists claimed that people with blood group 'O' or 'Rh' negative may be at slightly lower risk of Coronavirus than people with other blood groups.Researchers in Canada have come to this conclusion by studying the reports of 225,556 Canadians who were tested for the Coronavirus and the report said, the risk for a COVID-19 diagnosis was lower in people with blood group 'O' versus those with 'A,' 'B,' or 'AB.'

The results of the Toronto based Canadian study were published on November 24 in the journal titled Annals of Internal Medicine. The report mentioned, the risk for a COVID-19 diagnosis was 12% lower and the risk for severe COVID-19 or death was 13% lower in people with blood group/type 'O' versus those with 'A,' 'B,' or 'AB.' The report also said, people in any blood group who were 'Rh' negative were also somewhat protected, especially if they had 'O' negative blood.

In October 2020 two medical studies have suggested that people with blood type 'O' may be at lower risk of contracting the novel coronavirus. The two studies were published on 15 October 2020 in the journal titled Blood Advances, a publication of the American Society of Haematology.

The first study of October 2020, a Danish study, conducted by 11 researchers based on information of 473,654 individuals tested for COVID-19, found that blood group 'O' was associated with a decreased risk of coronavirus infection. Similar results were found by the second study, a Canadian medical study conducted by 14 researchers based on data collected from 95 Covid-19 intensive care unit (ICU) patients in six metropolitan Vancouver hospitals. The two study results suggest that people with blood types 'A,' 'B,' or 'AB' may be more likely to be infected with COVID-19 than people with type 'O'.

Earlier, the California-based genetic testing company 23andMe said there was a link between coronavirus infection and the blood group. Scientists at Genetics Company 23andMe looked at more than 1 million DNA samples from its four-month genetic study of Covid-19 back in June 2020. According to its findings which have been published in a pre-print paper in September 2020 mentioned that people with blood type 'O' tend to test negative for the virus more frequently when compared to people with any other blood group.

Based on the genetic analysis of over 1 million participants (the preliminary findings released in June looked at 750,000) and a more diverse dataset, 23andMe scientists not only found a strong association between blood type and susceptibility but also the severity of the disease. The June 2020 results showed that of the 750,000 participants - including 10,000 outside of 23andMe that had been hospitalized with Covid-19 - those with blood type 'O' were 9-18 percent less likely to test positive than other blood types.

Even in March 2020 study conducted in Wuhan, Hubei Province, China, the epicentre of Covid-19 disease, found that coronaviruses can be easily transmitted to people with blood type 'A'. On March 18, the UK-based Daily Mail reported the results of the Chinese study.

Researchers in China looked at blood group patterns of more than 2,000 people who had been diagnosed with the new coronavirus as part of a preliminary study. They found that those with blood type 'A' were more vulnerable to infection and tended to develop more severe symptoms while those with the more common blood type 'O' had a "significantly lower risk" of getting the disease.

Various studies preliminary evidence suggest that people's blood type might be an important risk factor - both for being infected by the Coronavirus and for falling dangerously ill. But there are some opposite results also. After looking at thousands of additional patients with COVID-19, scientists have reported a much weaker link to blood type.

In July 2020 two studies - one at the Massachusetts General Hospital and the other at Columbia Presbyterian Hospital in New York - did not find that Type 'A' blood increases the odds that people will be infected with COVID-19. These two studies found no link between blood type/group and the severity of the illness caused by Coronavirus.

History Lesson (Blood types and diseases):

The notion that blood type/group might be linked to infectious disease susceptibility dates back decades:
A study published in 1977 found that people with type 'O' blood were more likely to become infected with cholera bacteria, and people with type 'A' blood were less likely. The study was conducted in the Philippines; cholera is rare in the US but on the rise globally.

The authors of a 1993 article suggested that people with type 'O' blood are more likely to become infected with Helicobacter pylori than people with 'A' or 'B' blood because their gastric mucosa has more receptors for the bacterium. "    In 2000 scientists said, with the bubonic plague, people with blood type 'A' showed the mildest symptoms than other blood group people.

"    In 2003, scientists suggested that a blood group antigen functioned as a receptor for coronavirus (formerly called Norwalk virus) docking. They found that in saliva, the virus bound efficiently to 'O' and 'A' antigens but less so to 'B' antigens."    In 2015 scientists revealed that people with blood type 'O' very rarely develop severe malaria and are very well-protected against its most severe form.

No need to worry about blood group and COVID-19 risk:
There are four main blood types: A, B, AB and O. Blood types were discovered in 1901 by the Austrian immunologist and pathologist Dr. Karl Landsteiner, who later won a Nobel Prize for his work. Like other genetic traits, one's blood type/group is inherited from his/her parents. It is said that despite the A, B, AB and O groups being discovered almost 120 years ago, scientists still do not fully understand their purpose.

A handful of studies have shown a link between blood type and Covid-19 and mentioned, people with type 'O' blood might be slightly more protected from the virus, and people with Type 'A' slightly more vulnerable. But there are important caveats to consider from the research results. There is zero indication that any blood type is either totally protective or dooms a patient to severe outcomes of Covid-19.

As far as we know, everyone is still at risk of getting the Coronavirus, and definitely at risk of being an asymptomatic carrier-and therefore of spreading it to others.The studies relating blood groups and Covid-19 only suggest an association between blood types and Covid-19 outcome, not cause and effect. So, the Public health experts say that people with any blood type need to take the same mitigation precautions to protect himself/herself from Coronavirus.

Spokesperson for the Infectious Diseases Society of America, Dr.Glatt said, "Any possible influence of blood type on COVID-19 appears small compared with the substantial impact of known risk factors, such as older age and underlying health conditions." So, people shouldn't jump to conclusions that they are safer or not because of their blood types/groups, he added.The bottom line is clear: Before getting any Corona vaccine or even getting the vaccine, the safest and most effective way to prevent the coronavirus or unknowingly spreading it to others is to keep wearing a mask and socially distancing from people-regardless of your blood type.

The writer is a Pharmacist and Doctoral Researcher of Massey University, New Zealand