A Malaysian Study on COVID-19 (SARS-CoV-2) Vaccination Immune Response in Haemodialysis patients: A prospective, multicenter, cohort study

Background: Patients with end-stage renal disease (ESRD) have compromised immune systems, possibly reducing their vaccine-induced antibody responses compared to the general population. This study aims to determine the immunogenicity of this group to the COVID-19 vaccine. Methods: Haemodialysis patients receiving the Pfizer-BioNTech mRNA vaccine were followed for at least 13 months. Blood samples were collected prior to every vaccine dose and at multiple intervals thereafter. Neutralising antibodies (nAb) against SARS-CoV-2 were measured. Patients voluntarily reported any COVID-19 infection. Results: Between April 2021 and January 2023, 271 patients received at least one dose of the vaccine; 212 of these had at least one blood sample tested for nAb. Booster doses were given 26.2 weeks after the second dose. nAbs were detected in 16.8% of patients before vaccination. The nAb levels were higher than the non-convalescent patients after the first dose, but it was not statistically significant. Breakthrough infections occurred in 29.3% patients. They were not associated with history of COVID-19 infection (p=0.188). There were 34 deaths (16.0%); 2 related to COVID-19. Younger age was associated with higher nAb reactivity post-first dose, but this difference diminished after the second dose. Conclusion: Almost complete seropositivity (98.4%) was achieved after two doses of vaccine. Sustained antibody levels after the third dose underscore the importance of a booster dose in protecting this vulnerable population. However, the occurrence of breakthrough infections highlights the need for continued monitoring, preventive measures, and further research to optimize vaccination strategies in haemodialysis patients.