ANTIBODY RESPONSE AFTER A BOOSTER DOSE OF SARS-COV-2 VACCINE IN LIVER TRANSPLANT RECIPIENTS AND THOSE WITH CHRONIC LIVER DISEASES

ABSTRACT

Background & Aimss Poor antibody (Ab) response after SARS-CoV-2 vaccination has been reported in liver transplant (LT) recipients and those with chronic liver diseases (CLD). The role of a booster dose in those with poor response to initial vaccination is not well defined in this patient population. Methods: In this prospective study, we studied LT recipients and those with CLD (with or without cirrhosis) who had poor antibody response to SARSCoV- 2 spike protein after 2 doses of mRNA vaccines or a single dose of JnJ vaccine. Antibodies (predominantly IgG) against receptor binding domain to SAR-CoV-2 spike protein was assessed using the Roche electrochemiluminescence, semi-quantitative immunoassay (Elecsys ® Ant-SARS-CoV2 semi-quantitative) via LabCorp. We defined poor Ab response as `undetectable' if Ab levels are ≤0.80 U/mL and `low' if levels are between 0.80 U/mL and 249.9 U/mL. Results: Of the 80 patients enrolled, 45 had LT, and 35 had CLD (18 with cirrhosis). The median days between standard vaccination and measurement of Ab titers (prebooster) was 41 days and post-booster dose was 28 days. A booster dose was given at a median of 138.5 days after the completion of the standard regimen Among these, 47 of 80 (59%) patients received booster doses with Pfizer, 27 (34%) Moderna, and 6 (7%) JnJ vaccine;the corresponding numbers for initial vaccination was 41 (51%), 24 (30%) and 15 (19%) respectively. After the booster dose, 58 (73%, 31 LT, 27 CLD) had good response (≥250 U/mL), and 22 (28%, 14 LT, and 8 CLD) had poor response (7 undetectable and 15 with low Ab levels). No patient had any serious adverse events. The favorable Ab responses were lower in those who had initial undetectable Ab levels Ab (<0.80 U/mL) than those who had low Ab levels (0.80-249 U/mL) after the standard vaccination regimen (42% vs. 87%, p=0.0001). There were no significant differences between the immunosuppressed (defined as liver transplant or at least one immunosuppressant medicine) and the immunocompetent patients in the antibody titer levels after booster vaccines. The antibody response after homologous and heterologous booster doses were similar. Conclusions: Booster dose can enhance Ab response in LT recipients and CLD patients who have a poor response to initial standard vaccine regimen. (Table Presented)