ABSTRACT
BackgroundRepeated vaccination against SARS-CoV-2 increases serological response in kidney transplant recipients (KTR) with high interindividual variability. No decision support tool exists to predict SARS-CoV-2 vaccination response in KTR. MethodsWe developed, internally and externally validated five different multivariable prediction models of serological response after the third and fourth vaccine dose against SARS-CoV-2 in KTR. Using 27 candidate predictor variables, we applied statistical and machine learning approaches including logistic regression (LR), LASSO-regularized LR, random forest, and gradient boosted regression trees. For development and internal validation, data from 585 vaccinations were used. External validation was performed in four independent, international validation datasets comprising 191, 184, 254, and 323 vaccinations, respectively. FindingsLASSO-regularized LR performed on the whole development dataset yielded a 23- and 11- variable model, respectively. External validation showed AUC-ROC of 0.855, 0.749, 0.828, and 0.787 for the sparser 11-variable model, yielding an overall performance 0.819. InterpretationAn 11-variable LASSO-regularized LR model predicts vaccination response in KTR with good overall accuracy. Implemented as an online tool, it can guide decisions when choosing between different immunization strategies to improve protection against COVID-19 in KTR.
ABSTRACT
Immunogenicity of SARS-CoV-2 vaccines in kidney transplant recipients is limited, resulting in inadequately low serological response rates and low immunoglobulin (Ig) levels, correlating with reduced protection against death and hospitalization from COVID-19. We retrospectively examined the time course of anti-SARS-CoV-2 Ig antibody levels after up to five repeated vaccinations in 644 previously nonresponding kidney transplant recipients. Using anti SARS-CoV-2 IgG/IgA ELISA and the total Ig ECLIA assays, we compare antibody levels at 1 month with levels at 2 and 4 months, respectively. Additionally, we correlate the measurements of the used assays. Between 1 and 2 months, and between 1 and 4 months, mean anti-SARS-CoV-2 Ig levels in responders decreased by 14% and 25%, respectively, depending on the assay. Absolute Ig values and time course of antibody levels and showed high interindividual variability. Ig levels decreased by at least 20% in 77 of 148 paired samples with loss of sufficient serological protection over time occurring in 18 out of 148 (12.2%). IgG ELISA and total Ig ECLIA assays showed a strong positive correlation (Kendalls tau=0.78), yet the two assays determined divergent results in 99 of 751 (13.2%) measurements. IgG and IgA assays showed overall strong correlation but divergent results in 270 of 1.173 (23.0%) cases and only weak correlation of antibody levels in positive samples. Large interindividual variability and significant loss of serological protection after 4 months supports repeated serological sampling and consideration of shorter vaccination intervals in kidney transplant recipients.
ABSTRACT
Mortality from COVID-19 among kidney transplant recipients (KTR) is high, and their response to three vaccinations against SARS-CoV-2 is strongly impaired. We retrospectively analyzed serological response of up to five doses of SARS-CoV-2 vaccine in KTR from December 27, 2020, until December 31, 2021. Particularly, the influence of different dose adjustment regimens for mycophenolic acid (MPA) on serological response to fourth vaccination was analyzed. In total, 4.277 vaccinations against SARS-CoV-2 in 1.478 patients were analyzed. Serological response was 19.5% after 1.203 basic immunizations, and increased to 29.4%, 55.6%, and 57.5% in response to 603 third, 250 fourth and 40 fifth vaccinations, resulting in a cumulative response rate of 88.7%. In patients with calcineurin inhibitor and MPA maintenance immunosuppression, pausing MPA and adding 5 mg prednisolone equivalent before the fourth vaccination increased serological response rate to 75% in comparison to no dose adjustment (52%) or dose reduction (46%). Belatacept-treated patients had a response rate of 8.7% (4/46) after three vaccinations and 12.5% (3/25) after four vaccinations. Except for belatacept-treated patients, repeated SARS-CoV-2 vaccination of up to five times effectively induces serological response in kidney transplant recipients. It can be enhanced by pausing MPA at the time of vaccination.
ABSTRACT
Transplant recipients exhibit an impaired protective immunity after SARS-CoV-2 vaccination, potentially caused by mycophenolate (MPA) immunosuppression. Recent data from autoimmune patients suggest that temporary MPA hold might significantly improve booster vaccination outcomes. We applied a fourth dose of SARS-CoV-2 vaccine during temporary (5 weeks) MPA hold to 29 kidney transplant recipients, who had not mounted a humoral immune-response to previous vaccinations. Seroconversion until day 32 after vaccination was observed in 76% of patients, associated with acquisition of virus neutralizing capacity. Interestingly, 21/25 (84%) CNI-treated patients responded, but only 1/4 Belatacept-treated patients. In line with humoral responses, counts and relative frequencies of spike receptor binding domain (RBD) specific B cells were significantly increased on day 7 after vaccination, with an increase in RBD specific CD27++CD38+ plasmablasts. Whereas overall proportions of spike-reactive CD4+ T cells remained unaltered after the fourth dose, frequencies were positively correlated with specific IgG levels. Importantly, antigen-specific proliferating Ki67+ and in vivo activated PD1+ T cells significantly increased after re-vaccination during MPA hold, whereas cytokine production and memory differentiation remained unaffected. In summary, MPA hold was safe and augmented all arms of immunity during booster vaccination, suggesting its implementation in vaccination protocols for clinically stable transplant recipients.
ABSTRACT
BackgroundAntigen-detecting rapid diagnostic tests (Ag-RDT) for SARS-CoV-2 offer new opportunities for the quick and laboratory-independent identification of infected individuals for control of the SARS-CoV-2 pandemic. Despite the potential benefits, nasopharyngeal sample collection is frequently perceived as uncomfortable by patients and requires trained healthcare personnel with protective equipment. Therefore, anterior nasal self-sampling is increasingly recognized as a valuable alternative. MethodsWe performed a prospective, single-center, point of care validation of an Ag-RDT using a polypropylene absorbent collector for standardized self-collected anterior nasal swabs. Real-Time Polymerase Chain Reaction (RT-PCR) from combined oropharyngeal/nasopharyngeal swabs served as a comparator. Primary endpoint was sensitivity of the standardized Ag-RDT in symptomatic patients with medium or high viral concentration ([≥] 1 million RNA copies on RT-PCR for SARS-CoV-2). ResultsBetween February 12 and March 22, 2021, 388 participants were enrolled. After exclusion of 9 patients for which no PCR result could be obtained, the novel Ag-RDT was evaluated based on 379 participants, of which 273 were symptomatic and 106 asymptomatic. In 61 samples from symptomatic patients with medium or high viral load ([≥] 1 million RNA copies), the sensitivity of the standardized Ag-RDT was 96.7% (59/61; 95%CI: 88.7-99.6%) for the primary endpoint. In total, 62 positive Ag-RDT results were detected out of 70 RT-PCR positive individuals, yielding an overall sensitivity of 88.6% (95%CI: 78.7-94.9%). Specificity was 99.7% (95%CI: 98.2-100%) in 309 RT-PCR negative individuals. ConclusionHere, we present a validation of a novel Ag-RDT with a standardized sampling process for anterior nasal self-collection, which meets WHO criteria of [≥]80% sensitivity and [≥]97% specificity. Although less sensitive than RT-PCR, this assay could be beneficial due to its rapid results, ease of use, and suitability for standardized self-testing. (Funded by Dragerwerk AG & Co. KGaA, Lubeck, Germany; ClinicalTrials.gov number NCT04698993)
