Blood Type O Protective, Dexamethasone May Save Lives & US Cases Trending Up

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Blood Type O Protective, Dexamethasone May Save Lives & US Cases Trending Up

Written by Dr. Larry, powered by Averpoint



“At home, we added 158K cases, bringing our total to 2.1 million. While national numbers remain flat, the virus is declining in the northeast and surging in the South and West. (1)

  • Texas, Arizona, Alabama, and South Carolina are among many states with record daily number. 
  • Florida had over 3,000 cases yesterday, concerning given its elderly population.
  • Despite its record numbers, California started its phased return to work this week.

This is a global pandemic spreading quickly through Asia, Africa, and Latin America.  The world added over 1 million new cases in just 1 week, bringing the total infected to 8 million. (2)

India, which ended a nationwide lockdown, is spiking and crowded cities are near hospital capacity. China saw its first outbreak in 8 weeks, and the government quickly shut down a region. You can always refer to the Johns Hopkins coronavirus resource center to follow these trends.


A major study published on Wednesday in the NEJM corroborated the finding that blood type may have an effect on coronavirus susceptibility. (3) Let’s back up and talk about blood types for a minute. Everyone’s blood is one of four types: A, B, AB, or O. Most people in the US are A or O. (4) The gene that determines blood type encodes for an enzyme that attaches a molecule to the surface of your red blood cells. If you are type A, you have the enzyme that attaches A, if you’re B, you have the enzyme that attaches B, and if you’re AB, you have both. Being type O just means you have neither enzyme.

Previous studies out of China and Columbia University have raised the possibility that blood type may have an effect on coronavirus: they found that people with COVID19 were less likely to be blood type O than the general population, but the research is still preliminary and not yet peer-reviewed. (5) This new study is something called a GWAS, or “Genome Wide Association Study”, that looked across the entire genetic code of patients with severe COVID19 and healthy controls, for  differences in their genes. (6)

The gene that encodes for blood type was found to be highly predictive of respiratory failure. Blood type O was the most protective, with a 35% decreased odds of needing oxygen or ventilation, and blood type A was the most at risk, with 45% increased odds.


So why would your blood type affect your chances of getting infected? 

We don’t know for sure yet, but there are several possibilities: 

  • First, people make antibodies to the blood antigens they don’t have. People who are blood type O make the most anti-A, an antibody that has been shown to bind to the spike protein on the surface of the SARS virus. These antibodies may also offer some protection against the virus that causes COVID19. (7)
  • Your blood type also plays a role in how quickly your blood clots, and COVID19 patients at risk of developing blood clots, so blood type could have an effect though this mechanism.
  • Blood group enzymes have effects far beyond your red blood cells, so your blood type may be protective against coronavirus in a way we haven’t yet figured out.

The bottom line is, while more research is still needed, you can probably breathe a little easier if you are blood type O, and should perhaps be more cautious if you’re A.

It’s important to note that NO STUDY to date has found an association of blood type and death rate from COVID19, so it’s important to stay vigilant with social distancing, hand-washing, and wearing a mask when in close contact with others.


Let’s talk about treatment for a moment. This week, preliminary results of a British study showed that the steroid Dexamethasone may save lives of sick COVID19 patients. Up until this point, studies on steroids for COVID19 patients had failed to show benefits, and some showed worse outcomes.

In the preliminary British data, 2100 patients, the mortality improved by ⅓ for ventilated or the sickest patients. This $8 medication could be used worldwide (vs the 4-10,000 price tag of Remdesivir), but doctors await the release of the full study details, and for the benefits of steroids to be reproducible in additional studies.  

We will follow this story for you.



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