What is pernicious anemia?

An autoimmune : Disorder where your body makes antibodies so you can not absorb vitamin B12 so it has to be given by a shot to bypass the stomach and go directly into the bloodstream

Pernicious anemia: It's a condition which results in low vitamin B12 leading to anemia. The person affected with this condition needs the B12 supplement by injection route as oral absorption is impaired.

Low B12: Secondary to absorb it, or secondary to not eating it with your food. True vegans will develop it from inadequate intake. Must take supplemental B12!