Safety and Immunogenicity of Anti-SARS-CoV-2 Booster Dose in Patients with Chronic Liver Disease

: The low response to vaccines is a well-known problem in cirrhosis. We evaluated the safety and immunogenicity of booster doses in patients with chronic liver disease (CLD), comparing the humoral response in cirrhotic vs. non-cirrhotic patients, and the impact of different factors on immune response. From September 2021 to April 2022, outpatients with CLD who completed the primary vaccination course and the booster dose against SARS-CoV-2 were enrolled. Blood samples were collected after second and third doses for detecting anti-spike protein IgG. We enrolled 340 patients; among them, 91 subjects were cirrhotic. After primary vaccination course, 60 (17.6%) patients did not develop a positive antibody titer, without significant differences between cirrhotic and non-cirrhotic patients (p = 0.076); most of them (88.3%) developed it after booster dose. At multivariable analysis, factors associated with higher humoral response after booster dose were only porto-sinusoidal vascular disorder (p = 0.007) as an etiology of CLD and the use of the mRNA-1273 vaccine (p = 0.001). In conclusion, in patients with CLD, a booster dose against SARS-CoV-2 induces an excellent immunogenicity and leads to an adequate antibody response. Cirrhosis is not associated with a worse humoral response, compared to patients with non-cirrhotic CLD.