Antibody response to mRNA SARS-CoV-2 vaccine among kidney transplant recipients – Prospective cohort study

Rozen-Zvi, Benaya; Yahav, Dafna; Agur, Timna; Zingerman, Boris; Ben-Zvi, Haim; Atamna, Alaa; Tau, Noam; Mashraki, Tiki; Nesher, Eviatar; Rahamimov, Ruth

OBJECTIVES: We aimed to evaluate rates of antibody response to mRNA SARS-CoV-2 vaccine among kidney transplant recipients, and to identify factors associated with reduced immunogenicity. METHODS: A prospective cohort study including consecutive kidney transplant recipients in a single referral transplant center. Participants were tested for anti-spike (anti-S) antibodies 2-4 weeks following second vaccine dose. Primary outcome was rate of seropositivity. Univariate and multivariate analyses were conducted to identify factors associated with seropositivity. RESULTS: Of 308 kidney transplant recipients included, only 112 (36.4%) tested positive for anti-S antibodies 2-4 weeks after receiving the second dose of BNT162b2 vaccine. Median antibody titer was 15.5 AU/mL (interquartile range [IQR] 3.5-163.6). Factors associated with antibody response were higher estimated glomerular filtration rate (eGFR) (odds ratio [OR] 1.025 per ml/min/1.73m(2), 95% confidence interval [CI] 1.014 - 1.037, p<0.001), lower mycophenolic acid dose (OR 2.347 per 360 mg decrease, 95% CI 1.782 - 3.089, p<0.001), younger age (OR 1.032 per year decrease, 95% CI 1.015 - 1.05, p<0.001) and lower calcineurin inhibitors (CNI) blood level (OR 1.987, 95% CI 1.146 - 3.443, p=0.014). No serious adverse events to the vaccine were reported. CONCLUSIONS: Kidney transplant recipients demonstrated inadequate antibody response to mRNA SARS-CoV-2 vaccination. Immunosuppression level was a significant factor in this response. Strategies to improve immunogenicity should be examined in future studies.