I, too, at 75 years of age, have never had an anemia or RBC problem. One or two months after one Moderna vaccination, actually getting CoVid and a Regeneron infusion, I noticed that my hair, in addition to getting extremely thin, had gotten dry, brittle, and began breaking off, one to two inches from my scalp. Had my iron checked and the iron was below the normal range and ferritin was so low that it was just about out of range as well, on the low side. Doctor put me on iron pills but to this date, five months later, I don't see any improvement. I have not yet had the level of iron in my blood re-checked. I believe this is either related to having had the virus or the vaccination.