Study Linking COVID-19 to Blood Type

Human blood has many components.  One way to classify human blood is by blood type.  Four blood types exist: Type A, Type B, Type AB and Type O.  What distinguishes one type of blood from another are the antigens on the surface of the cell.  Antigens are proteins on the surface of a blood cell that play a role in identifying foreign cells in the blood stream. Those with Type A blood have antigens different from those with Type B blood.  Individuals with Type AB blood possess antigens particular to Type A blood and Type B blood.  Those with Type O blood have no antigens on the surface of their red blood cells. 
 
In the United States, about 45% to 50% of individuals have Type O blood.  Type A blood is present approximately 35% to 40% of the US population.  Type B blood is present in about 15% of the population.  As the math suggests, Type AB is the least common blood type, as it is found in only about 5% of the US population.    
 
Recently published data collected from patients treated at Wuhan Jinyintan Hospital in China reports a link between blood type and susceptibility to COVID-19.  Reviewing blood group distribution in 1,775  individuals who tested positive for COVID-19, the affected individuals had the following blood types:

• Type A: 37.75%
• Type B: 26.42%
• Type O: 25.80%
• Type AB: 10.03%

 
To understand the incidence of particular blood types in that region of China, researchers also collected data from 3694 healthy individuals who resided in Wuhan. Within that group, blood types were observed with the following frequency:

• Type O: 33.84%
• Type A: 32.16%
• Type B: 24.90%
• Type AB: 9.10%

 
Although individuals with Type O blood made up the greatest percentage (33.84%) of Wuhan residents who were healthy, the researchers found that individuals with Type A blood made up the greatest percentage (37.75%) of those who had fallen ill.  Although more people in Wuhan have Type O blood, more people with Type A blood fell ill.   
 
Based upon their evaluation of this evidence, the researchers concluded that individuals with Type A blood are at higher risk for contracting COVID-19.  Conversely, individuals with Type O blood have a lower risk of contracting COVID-19.
 
As this article has yet to undergo the rigorous peer evaluations that are required before a medical study like this one can be published, its findings are preliminary.  Nonetheless, it is likely that this correlation will be studied further as more data becomes available.
 
A copy of the article can be viewed here:
https://www.medrxiv.org/content/10.1101/2020.03.11.20031096v1
 

---