Antibody response to ChAdOx1 nCoV‐19 (Covishield®) vaccine in people on maintenance hemodialysis

Abstract

Introduction: People on renal replacement therapy (RRT) have a high risk of COVID‐19 infection and subsequent death. COVID‐19 vaccination is strongly recommended for those on RRT. Data are limited on the immune response of the ChAdOx1 nCoV‐19/AZD1222 (Covishield®) vaccine in patients on RRT. Methods: A prospective cohort of adult (age > 18 years), on RRT in the form of hemodialysis were included and received two intramuscular doses of Covishield®. A blood specimen of 5.0 mL was collected at two time points, within a few days before administering the first dose of the vaccine and at 4–16 weeks after the second dose. According to their prior COVID‐19 infection status, the participants were grouped as (i) prior symptomatic COVID‐19 infection, (ii) prior asymptomatic COVID‐19 infection, and (iii) no prior COVID‐19 infection. Results: A large proportion (81%) of participants had anti‐spike antibodies (ASAb) before vaccination, and a reasonable proportion (30%) also had neutralizing antibodies (NAb). The titer of ASAb was relatively low (207 U/mL) before vaccination. The ASAb titer (9405 [1635–25,000] U/mL) and percentage of NAb (96.4% [59.6–98.1%]) were markedly increased following the administration of two doses of the vaccine. The participants' prior COVID‐19 exposure status did not influence the rise in ASAb titer and NAb percentage. Further, administering two doses of the Covishield vaccine helps them achieve a high ASAb titer. Conclusion: Two doses of ChAdOx1 nCoV‐19/AZD1222 (Covishield®) vaccine, given 12 weeks apart, achieve a high titer of ASAb and a high percentage of NAb in people on hemodialysis.