O

Chatter about the relationship between blood type and vulnerability to the COVID-19 virus got me curious. I don’t even know what the difference between blood types is (didn’t do high school biology). So I took me a dip into Wikipedia.

First a little history https://en.wikipedia.org/wiki/Blood_type

Blood types were first discovered by an Austrian physician, Karl Landsteiner.
In 1901, he made a definitive observation that blood serum of an individual would agglutinate with only those of certain individuals. Based on this he classified human bloods into three groups, namely group A, group B, and group C. He defined that group A blood agglutinates with group B, but never with its own type. Similarly, group B blood agglutinates with group A. Group C blood is different in that it agglutinates with both A and B. This was the discovery of blood groups for which Landsteiner was awarded the Nobel Prize in Physiology or Medicine in 1930. (C was later renamed to O after the German Ohne, meaning without, or zero, or null.)

Quick aside — animals also have blood types, but different to humans:
- Over 13 canine blood groups have been described.
- A majority of feline blood types are covered by the AB blood group.
- Horses have eight blood groups.
- And nine in cattle.

So back to human blood types.

As of 2019, a total of 41 human blood group systems are recognized by the International Society of Blood Transfusion (ISBT). The two most important blood group systems are ABO and Rh; they determine someone’s blood type (A, B, AB, and O, with +, − or null denoting RhD status) for suitability in blood transfusion.

For purposes of this discussion, let’s focus on the ABO system as it is relatively easy to grasp. It is a classification of blood, based on the presence and absence of antibodies and inherited antigenic substances on the surface of red blood cells — here’s a quick diagram:

The ABO blood group system involves two antigens and two antibodies found in human blood. The two antigens are antigen A and antigen B. The two antibodies are antibody A and antibody B. The antigens are present on the red blood cells and the antibodies in the plasma. The antigen property of the blood of all human beings can be classified into 4 groups, those with antigen A (group A), those with antigen B (group B), those with both antigen A and B (group AB) and those with neither antigen (group O).

Although the figures seem a little out of date, the information at https://en.wikipedia.org/wiki/Blood_type_distribution_by_country indicate that O is the most common type at around 40% of the population, A & B roughly similar, and AB very rare at under 10%.

Blood type is inherited, therefor race and ancestry largely determine blood type. However, looking at a map of blood type distribution by native population won’t help us. Colonialisation, immigration and a general melding of races requires that we look at current distribution regardless of ethnicity. I suspect that the data are fuzzy, but the conjecture is that individuals with Type-O blood are less susceptible to the virus, so here is a map of blood group O:

This is provided by a chap called Rob who seems to spend his time playing around with data: http://robslink.com/SAS/democd74/blood_type_map.htm and he got his figures from http://www.rhesusnegative.net/themission/bloodtypefrequencies/

And then we can compare it to the CDC’s COVID Data Tracker https://covid.cdc.gov/covid-data-tracker/#global-counts-rates:

And the short answer would appear to be “No”.
There does not seem to be any clear correlation between blood type and COVID vulnerability, but I have definitely learned a bunch.
Apparently, native Japanese have as many AB’s as O’s.
Native South Americans are 100% O.
Laplanders, Hawaiians, Maoris, Portuguese, Swiss and Norwegians are mainly A’s — I cannot see the connection?
And Mongolians, Indians and Siberians are mainly B’s.

There is piles of information and there are many more qualified folk than I delving, but it was worth the look.