The aim of this study was to estimate the incidence of COVID-19 disease in the French national population of dialysis patients, their course of illness and to identify the risk factors associated with mortality. Our study included all patients on dialysis recorded in the French REIN Registry in April 2020. Clinical characteristics at last follow-up and the evolution of COVID-19 illness severity over time were recorded for diagnosed cases (either suspicious clinical symptoms, characteristic signs on the chest scan or a positive reverse transcription polymerase chain reaction) for SARS-CoV-2. A total of 1,621 infected patients were reported on the REIN registry from March 16th, 2020 to May 4th, 2020. Of these, 344 died. The prevalence of COVID-19 patients varied from less than 1% to 10% between regions. The probability of being a case was higher in males, patients with diabetes, those in need of assistance for transfer or treated at a self-care unit. Dialysis at home was associated with a lower probability of being infected as was being a smoker, a former smoker, having an active malignancy, or peripheral vascular disease. Mortality in diagnosed cases (21%) was associated with the same causes as in the general population. Higher age, hypoalbuminemia and the presence of an ischemic heart disease were statistically independently associated with a higher risk of death. Being treated at a selfcare unit was associated with a lower risk. Thus, our study showed a relatively low frequency of COVID-19 among dialysis patients contrary to what might have been assumed.

Introduction: The aim of this study is to report our clinical hemodialysis experience using a percutaneous arteriovenous fistula (pAVF) created with the Ellipsys® vascular access system. This pAVF device creates a permanent AVF anastomosis between the proximal radial artery (PRA) and the deep communicating vein (DCV) in the proximal forearm. Methods: The medical records of all patients with a pAVF were retrospectively reviewed. The clinical data analyzed included reliability of pAVF use, quality of dialysis, rate and success of puncture, and pAVF related complications, along with incidence of subsequent interventions. Findings: Between May 2017 and November 2018, 34 patients had a pAVF created with technical success in 33 patients (97%). Twenty‐eight out of 34 (82%) patients had successful two‐needle cannulation within 10 days to 6 weeks after pAVF creation. The mean Kt/v was 1.6 (1.2‐2) and the average recirculation was 10%. Fifteen patients (44%) needed no further access intervention. Twelve patients (35%) required an additional procedure to assist maturation of the pAVF in order to facilitate puncture. The average blood flow measured at the brachial artery, before the first cannulation, was 850 ml/min. From causes unrelated to the procedure, four patients died during the follow‐up study. Two patients required revision to a surgical AVF. None of the pAVFs developed aneurysmal degeneration steal syndrome, or high access flow related issues. Discussion: The Ellipsys® pAVF offers a safe and functional vascular access for hemodialysis. Advantages included prompt access maturation, avoidance of high flow AVFs, and a simple nonsurgical procedure with high patient satisfaction. Functional outcomes are equivalent and likely better than surgical fistulas. There appears to be less aneurysmal degeneration and need for future re‐intervention. Objective dialysis parameters indicate excellent quality of hemodialysis for the patient.

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Background. The humoral response to SARS-CoV-2 infection in hemodialysis patients needs to be clarified. Methods. In this retrospective study performed in two dialysis facilities, we measured the circulating levels of SARS-CoV-2 antibodies in patients who were on maintenance hemodialysis during the first wave of the epidemic in March and April 2020 and were still alive 6 months later. We also investigated associations between the patients diagnosed as infected during the first wave and several clinical, biological, and radiological parameters of COVID-19. Finally, we compared these circulating levels of SARS-CoV-2 antibodies with those of a control group of healthcare workers infected during the same period. Results. Of the 299 hemodialysis patients who recovered from the first wave of the epidemic 6 months before, 59 had a positive SARS-CoV-2 antibody whereas only 45 patients were diagnosed as infected during the first wave of the epidemic. All infected hemodialysis patients developed circulating antibodies. Using a clustering method, a significant correlation was identified between the cluster with the lowest circulating levels of SARS-CoV-2 antibodies and the severity of COVID-19 based on several parameters including CRP, BNP, lymphocyte count, neutrophil-lymphocyte ratio, and oxygen requirements, as well as pulmonary involvement on chest scan. Moreover, the circulating levels of the SARS-CoV-2 antibodies in surviving hemodialysis patients (n = 59) were similar to those of the control group (n = 17). Conclusion. The main finding of this study is that all of the surviving hemodialysis patients who were diagnosed with SARS-CoV-2 infection from March to April 2020 developed a persistent humoral response with significant circulating levels of SARS-CoV-2 antibodies, 6 months later. Another important finding is that surviving hemodialysis patients who had more severe disease had lower circulating levels of SARS-CoV-2 antibodies. Finally, circulating levels of SARS-CoV-2 antibodies were similar in surviving hemodialysis patients and healthcare workers without kidney disease.

Background: Due to their immunocompromised conditions, hemodialysis (HD) patients are at high risk of being infected with SARS-CoV-2 with poor clinical outcomes. We explored safety, efficacy and variability factors associated with vaccine immune response in these patients. Methods: From 18 January to 30 April 2021, 87 HD patients were enrolled in this study and subdivided in two sub-groups: SARS-CoV-2 positive prior to vaccination and naïve patients. The vaccination protocol included two intramuscular shots of the mRNA vaccine at a 28-day interval. The vaccine response was evaluated one month after the first and second shots by measuring anti-S antibody titers. Findings: 44% of the patients studied, were women; median age was 58 years. One month after the first shot, 64.3% of patients had anti-S antibody titers < 50 U/mL while 96.5% had anti-S antibody titers > 250 U/mL one month after the second shot. We show that the anti-SARS-CoV-2 spike mRNA vaccine elicits a great tolerability in HD patients. Importantlly, the vaccine response is characterized by a higher rate of seroconversion than conventional vaccination, as we have shown for the hepatitis B vaccine. We highlight two major factors of variability of the vaccine response. First, pre-exposure to SARS-CoV-2 boosts humoral response, as 95% of SARS-CoV-2 positive patients developed anti-S antibody titers > 250 U/L just after the first shot. Secondly, on the contrary fluid overload strikingly appears, limiting the vaccine response, as 84% of HD patients with fluid overload elicit lower anti-S antibody titers after the first shot. Interpretation: Our findings show that the immunogenic profile induced by mRNA vaccines in HD patients represents a promising a protective strategy that is associated with greater tolerability. Fluid overload may be considered as a novel factor that hinders the immune response in HD patients and further studies will be needed to investigate this working hypothesis.