Immunogenicity of the Inactivated SARS-CoV-2 Vaccine (BBIBPCorV) in Hemodialysis Patients: A Case-Control Study

Abstract

Background: Studies have shown that immune responses to COVID-19 vaccines are impaired in dialysis patients, which may affect their immunity to vaccines. Therefore, this study aimed to evaluate SARS-COV-2 neutralizing antibodies in hemodialysis patients for 2 and 6 weeks after receiving inactivated Sinopharm vaccine. Method: In this study, 172 people were divided into two groups. The first group included 108 hemodialysis patients, while the second group included 64 health workers as a control group. To evaluate SARS-COV-2 neutralizing antibody titers, peripheral blood samples were collected from all participants 2 and 6 weeks after receiving the second dose of the Sinopharm vaccine. Samples were centrifuged, and the neutralizing antibody against the receptor-binding domain (RBD) was determined using the indirect ELISA technique. Results: Hemodialysis patients had lower IgG-neutralizing antibody titers than the control group (P <0.001). The titers of SARS-COV-2 neutralizing antibodies were not significantly different at two weeks compared to six weeks after vaccination (P=0.9204). Our findings showed a significant increase in titers of IgGneutralizing antibodies after vaccination in people with a history of COVID-19 (P=0.002). The seropositivity rate for neutralizing antibodies against RBD was significantly different between seropositive (immune) and seronegative (non-immune) patients six weeks after vaccination (P=0.022). Conclusion: The titers of neutralizing antibodies against SARS-COV-2 were lower in hemodialysis patients than in healthy individuals. This is probably due to the poor immune system. However, patients who received two doses of inactivated Sinopharm vaccine showed a higher antibody titer six weeks after vaccination.