Reevaluating Immunization Delays Post Red Blood Cell Transfusion

Current Canadian guidelines recommend to delay the measles, mumps, rubella (MMR) and varicella live attenuated vaccines by 6 months following transfusion of unwashed red blood cells (RBC) due to potential interference by serum antibodies. Thus, patients chronically transfused with RBC commonly suffer from a delay or absence of MMR and varicella vaccination. Over the last decades, not only has RBC handling changed, but also fewer blood donors have had natural mumps, measles and rubella infections, resulting in lower blood antibody levels. The recommendations may thus be unfounded and outdated, and prevent valuable vaccination opportunities for children with frequent blood transfusions