My husband is currently experiencing this same issue. His ferriten level is at 5, hemoglobin is down to 11.7, Hemotacrit 37.3, MCV 75.8, MCH 23.2, MCHC 31.3, RDW 15.9. They diagnosed him with microcytic anemia due to chronic blood loss. The did an endoscopy, colonoscopy, and yesterday a CT Enterography. All tests were negative for any abnormalities, bleeding, celiac, Chron's, etc. They want to do a camera endoscopy next, but I truly feel that will probably be just more money and no answers. We've already spent close to $5,000 out of pocket - which was worth every penny if he indeed had bleeding that needed addressing. He is now on prescription iron tablets twice a day. His B12 and foliate were NORMAL. I will continue to watch this post. Thanks to everyone who has shared information. We are NOT anti-vaccine. We very willingly, and happily took them and boosted as soon as we could. But, if this is a legitimate side effect, we should be told so, instead of chasing down a ghost. FYI - I had no problems at all, and my blood is checked every 6 months due to another autoimmune issues I have had since 2002.