Mix-and-Match Covid Boosters: Why They Just Might Work October 19, 2021 Auto Bot antibodies, Clinical Trials, Coronavirus (2019-nCoV), Food and Drug Administration, Immune System, Johnson & Johnson, Moderna Inc, Pfizer Inc, Vaccination and Immunization 0 The F.D.A. may authorize booster shots of vaccines different from the ones that Americans originally received. The science behind the move is promising.