Their participants all received 3 doses of the original Moderna mRNA vaccine and then 1 dose of the Moderna bivalent original/BA.5 booster dose. Participants then either received a monovalent XBB.1.5 booster or a bivalent XBB.1.5/BA.5 booster with a median time of 8 months from their 4th dose. They compared participant blood sera immune responses just before they got their updated booster with 15 days after the updated booster. 14/