STUDY OF EFFICACY, IMMUNE RESPONSE AND SAFETY OF ChAdOx1 NCOV-19/COVISHIELD VACCINE IN LIVER TRANSPLANT RECIPIENTS FROM TERTIARY CARE CENTRE IN INDIA

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is not associated with an increased mortality in liver transplant (LT) recipients;however, they are at high-risk of severe COVID-19 complications. The efficacy or safety of COVID-19 vaccines have not been described in LT recipients and immunogenicity of vaccines against COVID-19 may be lower in liver transplant recipients as age, lower glomerular filtration rate, and enhanced immunesuppression are predictors of poor response to vaccination. We studied the safety and immunogenicity of ChAdOx1 nCoV- 19/Covishield vaccine in LT recipients. Methods: We enrolled 15 LT recipients, two doses of ChAdOx1 nCoV- 19/Covishield vaccine were administered at an interval of 4-6 weeks. To assess the immune response, samples were collected at baseline, 28 days then 14 days after second dose to measure the SARS Cov2 S1 anti-spike total antibody (IgG, IgM and IgA), S1 Anti-spike RBD IgG and Surrogate neuralization assay were done. Adverse events following immunization (AEFI) and breakthrough infections were documented. Results: Of the 15 patients enrolled, mean age was 55 years (IQR 46-76), with male predominance (86.7%), median duration after transplant was 1611 days (IQR 630- 3931). Blood group B was most common (53.3%), followed by 0 (20%), A and ab (26.6%). 3 LT recipients had prior infection 8 months before and 3 developed breakthrough infection after first dose which were mild. Baseline antibodies were positive in 5, suggesting asymptomatic infection in 2 patients. 2 patients not mounting an IgG response even 14 days after 2nd dose were non-responders, 7 seroconverted to medium level antibodies (6.31-12.3 S/CO) and 1 developed a high antibody response (18.6 S/CO). Neutralizing antibodies were present in 66.6% of the cases. No serious AEFI were reported, mild diarrhoea and fever were reported in 1 case each. Conclusion: This is the first study on immune response and safety of ChAdOx1 nCoV- 19/Covishield vaccine in LT recipients. Vaccine was well tolerated with no serious adverse event in LT recipients and even single dose gave protection against serious disease. Protective immune response was seen in two third of the patients. One third had no or inadequate immune response making them vulnerable to risk of serious SARS CoV2 infection.