No. My RBC was not affected by vaccines or getting covid. If your numbers are in the range for anemia, it would be good to have a complete blood panel and document any symptoms that you might have. Anemia can be associated with a number of causes and diseases. As an aside, I have celiac disease (gluten) and around 20% of undiagnosed folk have anemia due to malabsorption of nutrients (GI damage). Fourteen years ago the gastroenterologist dismissed that I have celiac because I wasn't anemic, so I wasn't tested for it in the scans/biopsies. Irksome what doctors don't look for. The celiac was triggered by catching the H1N1 virus.