Abstract
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.
Highlights
In 2020, COVID-19 became the third leading cause of death worldwide, with a devastating effect on chronic kidney disease (CKD) patients
Chronic Kidney Dialysis (CKD) patients are more susceptible to infections due to their immunocompromised profile, as reflected by a defective vaccine response to BCG, influenza, and hepatitis viruses [12]
Our study highlights the efficacy and the immunogenic profile of the SARS-CoV-2 Messenger RNA (mRNA) vaccine which elicits in most patients (>98%) a significant humoral immune response against the SARS-CoV-2 spike protein after complete vaccination, with a higher seroconversion rate than the hepatitis B
Summary
In 2020, COVID-19 became the third leading cause of death worldwide, with a devastating effect on chronic kidney disease (CKD) patients. A large study in a healthy population showed that a two-dose vaccination procedure reduced severe acute respiratory syndrome and subsequent death by greater than 90% [7] Due to their comorbidities dialysis patients were excluded from this pilot study [8], meaning that the immunogenic profile of mRNA vaccines in this population is poorly understood. We took advantage of this decision by health authorities to evaluate the tolerance and immune response of patients in our dialysis facility. Due to their immunocompromised conditions, hemodialysis (HD) patients are at high risk of being infected with SARS-CoV-2 with poor clinical outcomes. We highlight two major factors of variability of the vaccine response
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