Santos-Araújo C, Veiga PM, Santos MJ, Santos L, Romãozinho C, Silva M, Lucas C, Duarte ML, Haarhaus M, Haase M, Macário F
Nephrol Dial Transplant - (-) - [2021-10-11; online 2021-10-11]
Vaccination programs are essential for the containment of the COVID-19 pandemic, which has affected hemodialysis populations especially hard. Early reports suggest a reduced immunologic response to 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 hemodialysis patients. In a multicenter study, including 294 Portuguese hemodialysis patients who had received 2 doses of BNT162b2 with a three week interval, IgG-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 10UR/mL. Demographic and clinical data was retrieved from a quality registry. Adverse events were registered using a questionnaire. At M2, seroconversion was 93.1% with a median antibody level of 197.5U/mL (1.2-3237.0) and a median increase of 180.0U/mL (-82.9-2244.6) from M1. Age (beta -8.9; 95%CI: -12.88 to -4.91; P < 0.0001), ferritin > 600ng/mL (beta 183.93; 95%CI: 74.75 to 293.10; P = 0.001) and physical activity (beta 265.79; 95%CI: 30.7 to 500.88; P = 0.03) were independent predictors of SARS-Cov-2 antibody levels after two vaccine doses. Plasma albumin > 3.5g/dL independently predicted the increase of antibody levels between both doses (OR 14.72; 95%CI: 1.38 to 157.45; P = 0.03). Only mild adverse reactions were observed in 10.9% of patients. The SARS-Cov-2 vaccine BNT162b2 is safe and effective in hemodialysis patients. Besides age, iron status and nutrition are possible modifiable modulators of the immunologic response to SARS-Cov-2 mRNA vaccines. This data suggests 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.