Safety and efficacy of one and two booster doses of SARS‐CoV‐2 mRNA vaccines in kidney transplant recipients: A randomized clinical trial

Abstract

AbstractBackgroundKidney transplant recipients are at risk for a severe course of COVID‐19 with a high mortality rate. A considerable number of patients remains without a satisfactory serological response after the baseline and adjuvant SARS‐CoV‐2 vaccination schedule.MethodsIn this prospective, randomized study, we evaluated the efficacy and safety of one and two booster doses of mRNA vaccines (either mRNA‐1273 or BNT162b2) in 125 COVID‐19 naive, adult kidney transplant recipients who showed an insufficient humoral response (SARS‐CoV‐2 IgG <10 AU/ml) to the previous 2‐dose vaccination schedule. The primary outcome was the difference in the rate of a positive antibody response (SARS‐CoV‐2 IgG ≥10 AU/ml) between one and two booster doses at 1 month after the final booster dose.ResultsA positive humoral response was observed in 36 (62%) patients receiving two booster doses and in 28 (44%) patients receiving one booster dose (odds ratio [OR], 2.10, 95% confidence interval [CI], 1.02–4.34, p = .043). Moreover, median SARS‐CoV‐2 IgG levels were higher with two booster doses (p = .009). The number of patients with positive virus neutralizing antibody (VNA) levels was numerically higher with two booster doses compared to one booster dose, but without statistical significance (66% vs. 50%, p = .084). There was no significant difference in positive seroconversions rate and antibody levels between mRNA‐1273 and BNT162b2.ConclusionA higher number of kidney transplant recipients achieved a positive antibody response after two booster doses compared to one booster dose. image