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Abstract: PO0140

Time-Dependent Evolution of IgG Antibody Levels After First and Second Dose of mRNA-based SARS-CoV-2 Vaccination in Hemodialysis Patients: A Multicenter Study

Session Information

Category: Coronavirus (COVID-19)

  • 000 Coronavirus (COVID-19)


  • Santos Araujo, Carla Alexandra R., Diaverum Renal Services Group, Lund, Scania, Sweden
  • Mota Veiga, Pedro, Polytechnic Institute of Viseu, School of Education, Viseu, Portugal
  • Santos, Mário João Pereira Sequeira, Unilabs Portugal, Porto, Porto, Portugal
  • Santos, Lidia, Diaverum Portugal, Sintra, Portugal
  • Romãozinho, Catarina, Diaverum Portugal, Sintra, Portugal
  • Lucas, Carlos, Diaverum Renal Services Group, Lund, Scania, Sweden
  • Silva, Mónica Tavares, Diaverum Portugal, Sintra, Lisboa, Portugal
  • Duarte, Maryluz Lopes, Unilabs Portugal, Porto, Porto, Portugal
  • Haarhaus, Mathias, Diaverum Renal Services Group, Lund, Scania, Sweden
  • Haase, Michael, Diaverum Renal Services Group, Lund, Sweden
  • Macario, Fernando, Diaverum Renal Services Group, Lund, Scania, Sweden

Vaccination programs are essential for the containment of the COVID-19 pandemic, which has affected significantly the hemodialysis population. Early reports suggest a reduced immunologic response to COVID-19 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 from multiple centers 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 COVID-19 vaccine BNT162b2 is safe and effective in hemodialysis patients. Besides age, iron status and nutrition are possible modifiable modulators of the immunologic response to COVID-19 mRNA vaccines.

Positive IgG spike protein antibody response and antibody levels after BNT162b2 vaccination,just before (M1) and six weeks after (M2) the second administration of the vaccine.