evidence: Emily Osment, an American Red Cross spokesperson, said her organization has fielded questions from clients worried that vaccinated blood would be "tainted," capable of transmitting components from the covid vaccines. Red Cross officials said they’ve had to reassure clients that a covid vaccine, which is injected into muscle or the layer of skin below, doesn’t circulate in the blood. [...] In practical terms, blood centers have only limited access to donated blood that has not in some way been affected by covid. Based on samples, Katz estimated that as much as 60% to 70% of the blood currently being donated is coming from vaccinated donors. Overall, more than 90% of current donors have either been infected with covid or vaccinated against it, said Dr. Michael Busch, director of the Vitalant Research Institute, who is monitoring antibody levels in samples from the U.S. blood supply. [...] Last month, a woman facing a cesarean section for a high-risk pregnancy said she didn’t want blood from a donor who had had covid, recalled Cohn with AABB. "I said, ‘Listen, the alternative is you don’t get the blood and that’s what will affect you,’" Cohn said.