Humoral response after the fourth dose of the SARS-CoV-2 vaccine in the CKD spectrum: a prespecified analysis of the SENCOVAC study

Background

There is scarce evidence on fourth doses of SARS-CoV-2 vaccines in chronic kidney disease (CKD) patients. We have evaluated the humoral response and effectivity of the fourth dose in the CKD spectrum: non-dialysis CKD (ND-CKD), hemodialysis (HD), peritoneal dialysis (PD) and kidney transplant (KT) recipients.

Methods

This is a prespecified analysis of the prospective, observational, multicentric SENCOVAC study. In patients with CKD who had received a complete initial vaccination and one or two boosters and had anti-Spike antibody determinations 6 and 12 months after the initial vaccination, we analyzed factors associated to persistent negative humoral response and to higher anti-Spike antibody titers as well as the efficacy of vaccination on COVID-19 severity.

Results

Of 2186 patients (18% KT, 8% PD, 69% HD and 5% ND-CKD), 30% had received a fourth dose. The fourth dose increased anti-Spike antibody titers in HD (P = 0.001) and ND-CKD (P = 0.014) patients and seroconverted 72% of previously negative patients. Higher anti-Spike antibody titers at 12 months were independently associated to repeated exposure to antigen (fourth dose, previous breakthrough infections), previous anti-Spike antibody titers and not being a KT. Breakthrough COVID-19 was registered in 137 (6%) patients, of whom 5% required admission. Admitted patients had prior titers below 620 UI/ml and median values were lower (P = 0.020) than in non-admitted patients.

Conclusions

A fourth vaccine dose increased anti-Spike antibody titers or seroconverted many CKD patients, but those with the highest need for a vaccine booster (i.e. those with lower pre-booster antibody titers or KT recipients) derived the least benefit in terms of antibody titers. Admission for breakthrough COVID-19 was associated with low anti-Spike antibody titers.

[Preliminary results of the Spanish Society of Nephrology multicenter study of quality performance measures: hemodialysis outcomes can be improved]

INTRODUCTION

The Spanish Society of Nephrology "Quality in Nephrology Working Group" (QNWG) was created in 2002. The aims of this group are the identification, diffusion, implementation and consolidation of a systematic, objective and comprehensive set of quality performance measures (QPMs) to help along the improvement of patient care and outcomes on hemodialysis, by means of strategies of feedback and benchmarking, and the design of quality improvement projects. The objective of this study is to present the preliminary results of a set of quality performance measures obtained in a group of Spanish hemodialysis centers, as well as to evaluate the repercussion of the application of the aforementioned thecniques on the observed results.

METHODS

During 2007 a total of 28 hemodialysis units participated in the study; 2516 patients were evaluated. A specific software was designed and used to facilitate the calculation of CPMs in each unit. The clinical indicators used refered to dialysis adequacy; anemia; mineral metabolisme; nutrition; viral infections; vascular access; mortality, morbidity (number and days of hospital admissions); and renal transplant. Every three months each center received its own data and its comparison with the rest of the group.

RESULTS

Except for hemoglobin levels we observed a global improvement. The percentage of centers reaching the stablished standards defined by the QNWG passed from 65% to 90,9% for Kt/V Daugirdas II (> 1,3 in > that 80% of the patients); from 71,4 % to 77,2 % for PTH (> 30 % of patients with serum PTH between 150 and 300 pg/ml); and from 42,8 % to 63,5 % for phosphate (> 75 % of patients with a serum phsphate < 5,5 mg/dl). More than 50% of centers showed an improvement in their final results as compared with their own initial results in all analyzed CPMs. Those centers that did not obtained an improvement in their results started the study with better percentages of acomplishment than those that showed a significant improvement in QPMs. (80,6+/-15,4 versus 71,8+/-16,6 respectively; p<0,001)

CONCLUSIONS

We are starting to make progresses in our knowledge of clinical results in our hemodialysis units, although there is still a long way to go over. To monitor and share CPMs results within hemodialysis centers might help to improve their results as well as to reduce intecenters variability.

Comparison of Quantitative PCR and Antigenemia in Cytomegalovirus Infection in Renal Transplant Recipients

Cytomegalovirus infection is a common complication of renal transplantation. Antigen pp65 levels serve as indicators of viral load, although the technique is difficult to perform and interpret. We sought to determine whether quantitative PCR had a higher sensitivity and predictive value in CMV infection.

METHODS

The study included 100 renal transplant recipients who were screened for IgM and IgG at the time of admission. On days 7, 15, 30, 45, 60, 75, 90, 120, 180, and 360, antigenemia tests were performed on blood (pp65) and urine, and a quantitative PCR on blood. Among 59 patients recruited between November 2003 and August 2004 the mean age was 54.5 +/- 12.9 years. Two patients did not reach 90 days follow-up (3%); four patients have not surpassed 90 days (7%); 22, 120 days (37%); and 31, 180 days (53%). Ninety-three percent of patients showed anti-IgG CMV-positive titers with all being IgM CMV-negative at baseline. The patients at risk for infection were given valgancyclovir as prophylaxis throughout the study.

RESULTS

At 474 visits, 8 samples (2.4%) were positive with urine; 5 (1.4%) with pp65, and 15 (4.7%) with PCR. Among the 15 positive samples, two (>100,000 and 3250 copies) revealed agreement of positive IgM and shellvial test on urine; two (15,100 and 5670 copies), antigen pp65 1+; one (17,400 copies) with pp65 2+ and shellvial urine; two (99,400 and 28,300 copies) with pp65 1+ and shellvial urine; and eight remaining determinations, 749, 2250, 686, 928, 2250, 26600, 777, and 2790 copies. The rest of the tests were negative.

CONCLUSION

The preliminary results of this study demonstrated that quantitative PCR was a useful rapid tool for diagnosing and monitoring CMV infections.

[Cytomegalovirus viral load and antigenemia in the monitorization of prophylactic treatment with valganciclovir in renal transplant recipients]

Cytomegalovirus (CMV) disease is one of the most relevant infectious complications in solid organ transplant, and we must perform an appropriate prophylactic intervention. The goal of this study was to evaluate the effectiveness of prophylactic treatment with valganciclovir in renal transplant recipients in the first three months post transplantation by shell vial urine culture assay, and by measuring antigenemia (pp65) and CMV viral load, the latter by PCR. The population of the study included 100 renal transplant recipients. We analyzed the results of 36 patients recruited between November 2003 and July 2004 who were receiving a prophylactic oral treatment with valganciclovir, and who had finished the follow-up period of 90 days. The three tests mentioned above were performed on days 7, 15, 30, 45, 60, 75 and 90. No positive antigenemia was detected, the virus was cultured in a urine specimen and, in one patient, three measurements of viral load in serum were positive. Preliminary results of the study suggest that universal chemoprophylaxis with valganciclovir is effective for the prevention of CMV infection in renal transplant recipients and that, although all three tests used were useful, the measurement of CMV viral load seems to be the most appropriate method for monitoring these patients.