The blood type of B negative is also uncommon, occurring in "2% of Caucasian, 1% of African American, 0.4% of Asian and 1% of Latino American" populations, says the Red Cross.

Type B: A less common blood type, with less than 2% of people having B-negative blood and about 9% having B-positive blood ...

Now, scientists say the woman is the only known carrier of a new blood type called “Gwada negative.” It’s the only blood type ...

There are eight blood types: A positive, A negative, B positive, B negative, O positive, O negative, AB positive and AB negative. But which is the rarest?

This blood type can donate red blood cells to both B-positive and B-negative recipients. AB-Negative (AB-) Prevalence: Less than 1% of the population.