Immunogenicity and Safety of Homologous Chadox1 Ncov-19 and Heterologous Prime-Boost of Coronavac and Chadox1 Ncov-19 among Kidney Transplant Recipients: An Observational Prospective Cohort Study

ABSTRACT

Introduction: Kidney transplant recipients (KTRs) are at risk for substantial morbidity and mortality during COVID-19 infection. Vaccination for this group of patients is reccommended. However, immunogenicity and safety data after COVID-19 vaccination among KTRs remains limited. Method(s) We conducted an observational prospective trial involving KTRs at Chiang Mai University hospital, Chiang Mai, Thailand. The participants were received homologous ChAdOx1 nCoV-19 (AZ-AZ), or the heterologous prime-boost of CoronaVac,followed by AZ (SV-AZ). The immunogenicity was assessed by measuring antibodies against the S1 receptor-binding domain (anti-RBD), and SARS-CoV-2 surrogate virus neutralization test (sVNT) at specific timepoints. The primary outcome was the seroconversion rate of sVNT at day 28 after complete vaccination. The secondary outcomes were the seroconversion rate of sVNT at day 28 after the first dose of vaccination, the level of sVNT and anti-RBD at specific timepoints, and the adverse events of each vaccine regimen. Result(s) A total of 18 KTRs were recruited. Among those, 13 (72.2%), and 5 (27.8%) patients were received AZ-AZ, and SV-AZ regimen, respectively. The seroconversion rate of sVNT at day 28 after the second dose were 23.1%, and 20.0% for AZ-AZ, and SV-AZ, respectively (P>0.99). The level of sVNT and the level of anti-RBD at day 28 after the first and at day 28 after the second dose were not different between groups (Figure 1). There were no serious adverse events reported in any vaccine groups. However, AZ-AZ showed sign of tubular dysfunction demonstrated by increasing of fractional excretion of magnesium after complete course of vaccination which correlated to the trend of urine albumin and urine protein creatinine ratio (r=0.720, P=0.013;and r=0.726, P=0.011, respectively). [Formula presented] [Formula presented] Figure 1 Percentage of neutralization inhibition (a) and level of anti-RBD antibody (b) at each visit of homologous ChAdOx1 nCoV-19 (AZ-AZ), and heterologous prime-boost of CoronaVac, followed by AZ (SV-AZ) regimen Conclusion(s) Immunogenicity after COVID-19 vaccination with either homologous or heterologous prime-boost regimen among KTRs was compromised. Homologous replication-defective viral vectors vaccine regimen seemed to affect renal tubular function, and further follow-up should be warranted. No conflict of interestCopyright © 2023