A recent study by genetic testing company 23andMe of 750,000 people found that those who have blood type O were almost 20% less likely to catch the COVID-19 virus than those having other blood types.
People with type O blood were between 9% and 18% less likely to test positive for the disease. Backing up that statistic was the fact that people with Type O blood who had been exposed to COVID-19 were between 13% and 26% less likely to acquire the virus.
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The researchers at 23andMe concluded that there must be a link between the COVID-19 virus and the ABO gene that determines blood type.
Which blood type are you?
There are four main blood types: A, B, AB and O. On the surface of red blood cells are substances called antigens, and a person can have A antigens, B antigens, both or neither.
Someone is Type A if they have the A antigen, Type B if they have the B antigen, Type AB if they have both antigens, and Type O if they have no antigens. In addition, a protein called the Rhesus (Rh) factor is also present on red blood cells.
A person's blood type is designated Rh-positive if they have the Rh protein on their red blood cells, and Rh-negative if they don't, which results in eight possible blood types. The blood type chart below shows the percentage of Americans having each blood type:
- O positive - 37.4%
- O negative 6.6%
- A positive 35.7%
- A negative 6.3%
- B positive 8.5%
- B negative 1.5%
- AB positive 3.4%
- AB negative 0.6%
What is the most common blood type?
73.1% of all Americans have either the O positive or A positive blood types. O positive is the most common blood type, while AB- is the rarest, with only 0.6% of Americans having it.
People who are Rh-negative can only receive Rh-negative blood, while people who are Rh-positive can receive either Rh-positive or Rh-negative blood. Some people don't have an Rh charge in their blood at all, and they are called Rhnull. Their rarity is staggering.
Rhnull was first found in 1961 in an Aboriginal Australian woman. By 2010, only 43 people worldwide having Rhnull had been identified, and they are located in Brazil, Japan, China, the U.S., and Ireland. Their blood is called "golden blood" because it can be given to anyone having a rare blood type within the Rh system.
Your blood type determines who you can receive blood from and who you can donate blood to. Blood type O- is called "universal donor" because it can be given to anyone having any blood type. The following chart shows possible blood type compatibility:
|Blood Type||Can Donate To||Can Receive From|
|O Positive||O+, A+, B+ AB+||O+, O-|
|A Positive||A+, AB+||A+, A-, O+, O-|
|B Positive||B+, AB+||B+, B-, O+, O-|
|AB Positive||AB+ ONLY||All blood types|
|O Negative||All blood types||O- ONLY|
|A Negative||A-, A+, AB-, AB+||A-, O-|
|B Negative||B-, B+, AB-, AB+||B-, O-|
|AB Negative||AB-, AB+||AB-, A-, B-, O-|
How is blood type inherited?
We inherit our blood type from our parents. The chart below shows the possible blood types you can inherit from your parents:
Blood types were unknown when in 1818, the obstetrician James Blundell first performed a blood transfusion on a woman who had just given birth. After that, doctors experimented with transfusing lamb's blood and even cow's milk.
In 1909, Austrian biologist Karl Landsteiner first classified human blood into the four groups we know today. Moving to New York in 1937, Landsteiner along with forensic scientist Alexander Wiener discovered the Rhesus factor, which is the same as that found in the blood of Rhesus monkeys.
Why you should learn your blood type
You might need to find out your blood type for medical reasons or to get an international visa. According to the website The Healthy, people with Type AB, A, or B have a 40% increased risk of developing deep-vein thrombosis (DVT). This is where blood clots form in the lower legs and can travel to the lungs or brain with catastrophic consequences.
Also, according to The Healthy, those having non-O blood types have 25% to 30% higher levels of blood-clotting proteins called von Willebrand factor and Factor VIII. This causes them to have a 15% higher risk of dying from heart disease.
A study linked blood types, A, B, and AB to an increased risk of gastric cancer. This is possibly due to an inflammatory response to H. pylori bacteria, which is a cause of gastric ulcers.
Another study has shown that people having Type A or Type B are at up to 21% greater risk of developing Type 2 Diabetes compared to those having Type O. Those with Type B+ were at the greatest risk, and while scientists don't know why this is the case, it's thought that blood type influences the gastrointestinal microbiome, which in turn affects glucose metabolism and inflammation.
How to find out your blood type
1. Call your doctor
If you've ever had your blood drawn, ever been pregnant, or if you've undergone surgery, you most likely had a blood type test, and your doctor will have it on file.
2. Donate blood
You can find out your blood type while donating blood at the American Red Cross, America's Blood Centers, or various community facilities across the U.S. Not only will you learn your blood type, but you'll be helping patients undergoing surgery or accident victims.
You won't be able to donate blood unless you are 16-years-old or older, weigh at least 110 pounds (50 kg), if you are taking certain medications, have low iron levels, have recently visited a foreign country, or have donated blood within the last 56 days.
Canada offers free blood testing by the Canadian Blood Services, and they will inform you of your blood type instantly.
3. Use an at-home kit
Many pharmacies have at-home blood type testing kits that use either a card or vials of fluid to test your blood. The company leading the pack for sales on Amazon is Eldon, which sells an array of blood type testing kits on the site. The company promises results in just 2 minutes, and the kits come with an alcohol wipe, gauze, a lancet to prick your finger, plastic applicator sticks, and a card on which the blood is smeared.
The patches on a card or the vials of fluid cause your blood to clump instead of spreading out. This is a reaction to substances that are incompatible with your blood type. Once you see where your blood has clumped, you can use the instruction booklet included with the kit to determine your blood type.
If there are clumps in the Anti-A patch, your blood type is A, clumps in the Anti-B patch mean your blood type is B, clumps in the Anti-A and Anti-B patch mean your blood type is AB.
In the Anti-D patch, clumps mean you are Rh-positive, so add a + to your blood type. If there are no clumps in this patch, you are RH negative, and you can add a - to your blood type.
4. Use a telemedicine service
Companies such as Lemonaid partner with the lab testing company Quest Diagnostics. You pay Lemonaid a doctor fee and an additional $11.11 for a blood test, then go to one of the many Quest Diagnostics facilities across the U.S. to have your blood drawn.
The results are then sent to Lemonaid, who will provide you with a confidential report within three to five days.
A delicious meal for mosquitoes
According to The Healthy, if you have blood type O, you are up to twice as attractive to mosquitoes as those having type A, with those having Type B falling somewhere in between. In order to avoid serving up some of your delicious Type O blood, you may want to run out and buy some mosquito repellent.