Measuring anti-spike IgG Antibody Response to SARS-CoV-2 vaccination in Patients Receiving Hemodialysis in Pakistan

The current state of the evidence is equivocal for IgG antibody response to SARS-CoV-2 vaccination in hemodialysis patients. Here, we assess the immune response in hemodialysis patients who have received a complete series of vaccines with or without a history of prior COVID infection irrespective of the vaccine administered. In this cross-sectional study, we obtained serum samples from Hemodialysis patients (n = 101). Our study found that nearly three-quarters of patients (72.2%) had two doses of either Sinovac or Sinopharm vaccine administered, and ninety-seven percent of participants were considered seropositive (COVID Ab titers > 7.1 BAU/ml). Mean COVID19 spike antibody titers were 1892.4 BAU/mL and median titers were 971 BAU/mL. The comparative analysis was performed between patients who completed two-doses less than 6 months ago and more than 6 months ago when their antibody levels were measured. Mean and median antibody titers were 1895.8 and 792 BAU/mL in the former group compared to 1981.1 and 1033 BAU/mL respectively (P value 0.84) in the latter group, indicating no significant difference. There were also no statistically significant differences in IgG antibodies among subgroups defined by diabetes, hypertension, CAD or gender. However, older patients (age >55 years) had significantly higher anti-spike antibody titers as compared to younger patients (2417.8 BAU/mL vs 1377.3 BAU/mL, P value 0.008). The result of this study provides important evidence, which can lead to vaccine efficacy especially in older populations. Future studies should address whether booster vaccination may play a role in providing an effective and long-lasting protection among vulnerable patients undergoing hemodialysis treatment.