@wisner I’ve been taking HU for ten years and yes it really caused my RBC to go low. I was suffering from mild fatigue and thought it was the HU until this year when my GP noticed I was deficient in vitamin D 3 and put me on supplements. Within days the mild fatigue was gone although my RBC stayed low. HU also would send my WBC below normal. It was quite low during the pandemic. Surprisingly I didn’t get so much as a cold and never got Covid ( I did get multiple Covid shots). I may be getting off HU in a few weeks, fyi.