Serological Immune Response Following ChAdOx1 nCoV-19 Vaccine (Covishield

Introduction: Data are limited on antibody response to the ChAdOx1 nCoV-19 vaccine (AZD1222; Covishield®) in cirrhosis. We studied the antibody response following two doses of the ChAdOx1 vaccine, given 4−12 weeks apart, in cirrhosis. Methods: Prospectively enrolled, 131 participants (71% males; age 50 (43−58); alcohol-related etiology 14, hepatitis B 33, hepatitis C 46, cryptogenic 21, autoimmune 9, others 8; Child−Turcott−Pugh class A/B/C 52/63/16). According to dose intervals, the participants were grouped as ≤6 weeks (group I), 7−12 weeks (group II), and 13−36 weeks (group III). Blood specimens collected at ≥4 weeks after the second dose were tested for anti-spike antibody titre (ASAb; positive ≥ 0.80 U/mL) and neutralizing antibody (NAb; positive ≥20% neutralization) using Elecsys Anti-SARS-CoV-2 S (Roche) and SARS-CoV-2 NAb ELISA Kit (Invitrogen), respectively. Data are expressed as number (proportion) and median (interquartile range) and compared using non-parametric tests. Results: Overall, 99.2% and 84% patients developed ASAb (titre 5440 (1719−9980 U/mL)) and NAb (92 (49.1−97.6%)), respectively. When comparing between the study groups, the ASAb titres were significantly higher in group II than in group I (2613 (310−7518) versus 6365 (2968−9463), p = 0.027) but were comparable between group II and III (6365 (2968−9463) versus 5267 (1739−11,653), p = 0.999). Similarly, NAb was higher in group II than in group I (95.5 (57.6−98.0) versus 45.9 (15.4−92.0); p < 0.001), but not between the groups II and III (95.5 (57.6−98.0) versus 92.4 (73.8−97.5); p = 0.386). Conclusion: Covishield® induces high titres of ASAb and NAb in cirrhosis. A higher titre is achieved if two doses are given at an interval of more than six weeks.