Abstract
Background: The efficacy of SARS-CoV-2 vaccination among kidney transplant recipients (KTR) is low. The main goal of this study was to analyze factors that may influence the humoral response to vaccination. Methods: We analyzed the titer magnitude of IgG antibodies directed against spike (S)-SARS-CoV-2 antigen after the second dose of the mRNA vaccine in 142 infection naïve KTR (83 men, i.e., 58.4%) with a median age (IQR) of 54 (41–63), and 36 respective controls without chronic kidney disease. mRNA-1273 or BNT162b2 were applied in 26% and 74% of KTR, respectively. Results: S-specific immune response (seroconversion) was seen in 73 (51.41%) of KTR, and in all controls 36 (100%). Independent predictors of no response were elder age, shorter transplantation vintage, and a more than two-drug immunosuppressive protocol. In subgroup analyses, the seroconversion rate was highest among KTR without MMF/MPS treatment (70%), treated with no more than two immunosuppressants (69.2%), treated without corticosteroid (66.7%), younger patients aged <54 years (63.2%), and those vaccinated with the mRNA-1273 vaccine (62.16%). The independent predictors of higher S-antibody titer among responders were younger age, treatment with no more than two immunosuppressants, and the mRNA-1273 vaccination. Conclusions: Our study confirmed a low rate of seroconversion after vaccination with the mRNA vaccine in KTR. The major modifiable determinants of humoral response were the composition of the immunosuppressive protocol, as well as the type of vaccine. The latter could be taken into consideration when initial vaccination as well as booster vaccination is considered in KTR.
Highlights
In the advent of coronavirus disease 2019 (COVID-19) the vaccination of kidney and other solid organ transplant recipients (SOTR) has emerged as a tool protecting this high-risk population, whose case fatality ratio for COVID-19 otherwise ranges between 13 to over 30% [1]
Despite some concerns related to the risk of inducing rejection, which can be triggered by the vaccine antigen or an associated adjuvant, or by more specific cellular and humoral cross reactivity between vaccine epitopes and allograft antigens, two mRNA vaccines (BNT162b2/Pfizer and mRNA-1273/Moderna) authorized by regulatory agencies are widely applied in SOTR [2,3]
Clinical trials initiated after the outbreak of the COVID-19 epidemic proved the high efficacy of mRNA vaccines in the general population, reaching, after the second dose, 95% [2,3]
Summary
In the advent of coronavirus disease 2019 (COVID-19) the vaccination of kidney and other solid organ transplant recipients (SOTR) has emerged as a tool protecting this high-risk population, whose case fatality ratio for COVID-19 otherwise ranges between 13 to over 30% [1]. Kidney transplant recipients (KTR) demonstrated a markedly impaired seroconversion rate of 40–60% after two doses of mRNA vaccines [7,8,9]. Some preliminary studies presented a better seroconversion rate in SOTR receiving mRNA-1273 [11,13,14] These facts have mobilized the transplant community to evaluate the determinants of the response, and find measures to augment vaccine immunogenicity, given the likelihood that COVID-19 will remain a worldwide threat to the health of SOTR. Methods: We analyzed the titer magnitude of IgG antibodies directed against spike (S)-SARS-CoV-2 antigen after the second dose of the mRNA vaccine in 142 infection naïve KTR (83 men, i.e., 58.4%) with a median age (IQR) of 54 (41–63), and 36 respective controls without chronic kidney disease.
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