Time-dependent evolution of IgG antibody levels after first and second dose of mRNA-based SARS-CoV-2 vaccination in haemodialysis patients: a multicentre study.

BACKGROUND: Vaccination programs are essential for the containment of the coronavirus disease 2019 pandemic, which has hit haemodialysis populations especially hard. Early reports suggest a reduced immunologic response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines in dialysis patients, in spite of a high degree of seroconversion. We aimed to identify risk factors for a reduced efficacy of an mRNA vaccine in a cohort of haemodialysis patients. METHOD: In a multicentre study, including 294 Portuguese haemodialysis patients who had received two doses of BNT162b2 with a 3-week interval, immunoglobulin G-class antibodies against the SARS-CoV-2 spike protein were determined 3 weeks after the first dose (M1) and 6 weeks after the second dose (M2). The threshold for seroconversion was 10 UR/mL. Demographic and clinical data were retrieved from a quality registry. Adverse events were registered using a questionnaire. RESULTS: At M2, seroconversion was 93.1% with a median antibody level of 197.5 U/mL (1.2-3237.0) and a median increase of 180.0 U/mL (-82.9 to 2244.6) from M1. Age [beta -8.9; 95% confidence interval (95% CI) -12.88 to -4.91; P < 0.0001], ferritin >600 ng/mL (beta 183.93; 95% CI 74.75-293.10; P = 0.001) and physical activity (beta 265.79; 95% CI 30.7-500.88; P = 0.03) were independent predictors of SARS-CoV-2 antibody levels after two vaccine doses. Plasma albumin >3.5 g/dL independently predicted the increase of antibody levels between both doses (odds ratio 14.72; 95% CI 1.38 to 157.45; P = 0.03). Only mild adverse reactions were observed in 10.9% of patients. CONCLUSIONS: The SARS-CoV-2 vaccine BNT162b2 is safe and effective in haemodialysis patients. Besides age, iron status and nutrition are possible modifiable modulators of the immunologic response to SARS-CoV-2 mRNA vaccines. These data suggest the need for an early identification of populations at higher risk for diminished antibody production and the potential advantage of the implementation of oriented strategies to maximize the immune response to vaccination in these patients.

The type of SARS-CoV-2 vaccine influences serological response in kidney transplant recipients.

Vaccination is a promising strategy to control the ongoing pandemic; however, solid organ recipients tend to develop a weaker immune response to vaccination. Anti-spike SARS-CoV-2 antibodies titers were measured 2-4 weeks post-vaccination completion in 131 KT patients without previous infection. Demographic, clinical, and laboratorial parameters were analyzed to identify which factors contributed to seroconversion. Factors that influenced seroconversion, that occurred in 76 patients (58%), were longer time post-transplant, immunosuppression without an antiproliferative drug and vaccination with mRNA vaccines. Patients who received mRNA vaccines had significantly higher rates of seroconversion compared with adenovirus vector vaccines (67% vs 33%, P < .001) and higher anti-spike IgG titers. These findings reinforce the need to discuss the vaccination strategy in this population, including a third dose with a mRNA vaccine.