Efficiency of a boost with a third dose of anti-SARS-CoV-2 messenger RNA-based vaccines in solid organ transplant recipients.

A weak humoral response to two-doses of SARS-CoV-2 vaccine was observed in solid organ transplant (SOT) patients (1,2). Preliminary reports suggested the usefulness of a boost with a third dose (3) (4). Herein, we report the humoral response in 396 SOT patients (mean age 59 ± 15 years, 65 % men) who were given 3 doses messenger RNA-based vaccine (BNT162b2 vaccine [Pfizer-BioNTech]) (Table S1). Of these, 101 were included in our previous report (3). The two first doses were given one month apart, and the third dose was administered 59 (IQR25-75 : 47-67) days after the second dose, i.e. once the third dose was recommended by the French National Authority for Health.