Immunogenicity and safety of a booster COVID‐19 vaccination in patients with chronic liver disease: A multicenter study

Abstract Aim Patients with chronic liver disease (CLD), especially cirrhosis, are at a high risk of severe illness or death from coronavirus disease‐2019 (COVID‐19) and may have a suboptimal immune response to the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) vaccine. This study aimed to evaluate the safety and immunogenicity of the COVID‐19 booster vaccination in patients with CLD. Methods The study protocol was prospectively registered at ClinicalTrials.gov (No. NCT05204602) after approval by the Ethics Committee. Adult participants with CLD were enrolled in this multicenter prospective study. They completed two doses of the inactivated COVID‐19 vaccine and received booster doses at least 6 months later. Adverse reactions were recorded within 14 days after the booster dose. Serum samples of the enrolled patients were collected before and after booster vaccination and tested for SARS‐CoV‐2 receptor‐binding domain (RBD) immunoglobulin G and neutralizing antibodies. The chi‐squared or Fisher's exact test was used to compare categorical data, and the Mann–Whitney U test was used to compare continuous variables. Two‐sided p