Özet:

Background: As hemodialysis patients are among the vulnerable groups for severe COVID-19, proper vaccination of these patients is quite important. However vaccine responsiveness is generally reduced in hemodialysis patients and strategies should be developed to maintain protection in the long term. Objectives: This study aimed to analyse the changes in antibody levels of SARS-CoV-2 vaccinated hemodialysis patients after six months and to compare the effectiveness of inactivated and mRNA vaccines. Methods: Eighty-five hemodialysis patients were followed up for six months after their initial vaccinations for SARS-CoV-2. Persistence of humoral responses were compared between patients who got inactivated or mRNA vaccines and also between patients who received a booster dose and those who didn’t. SARS-CoV-2 antibody titers were measured by a commercial test that measures IgG antibodies toward the receptor-binding domain of spike protein. Results: Seropositivity that was achieved by initial vaccination dropped abruptly by 6 months. Patients who received a booster dose had significantly higher antibody levels than those who didn’t (1120,8 ± 983,3 AU/mL vs 313,3 ± 435,3 AU/mL respectively; p<0,001) and higher seropositivity as well (88% vs 65%). Seropositivity with mRNA vaccine at the end of 6th month was 81,8% while this decreased to 50% for inactivated vaccine. Patients who received mRNA vaccine initially or as the third dose could maintain 88,4% of seropositivtiy and this was higher than other patients who have just got inactivated vaccine (p=0,013). Conclusion: Humoral immune response by SARS-CoV-2 vaccines is not very stable in hemodialysis patients and planning the booster doses should not be delayed. mRNA vaccines have better immunogenicity than inactivated vaccines.

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