Tiza-<underline>T</underline>itre <underline>i</underline>ncrease and enhanced immunity through an adjuvanted, recombinant herpes <underline>z</underline>oster subunit v<underline>a</underline>ccine in patients with liver cirrhosis and post-liver transplantation: a study protocol for a prospective cohort study

Introduction Shingrix, an effective adjuvanted, recombinant herpes zoster vaccine (RZV), has been available since 2018. Immunocompromised patients are known to be predisposed to vaccine failure. In-vitro testing of immunological surrogates of vaccine protection could be instrumental for monitoring vaccination success. So far, no test procedure is available for vaccine responses to RZV that could be used on a routine basis.Methods and analysis This is a single-centre, three-arm, parallel, longitudinal cohort study aspiring to recruit a total of 308 patients (103 with a liver cirrhosis Child A/B, 103 after liver transplantation (both >= 50 years), 102 immunocompetent patients (60-70 years)). Blood samples will be taken at seven data collection points to determine varicella zoster virus (VZV) and glycoprotein E (gE)-specific IgG and T cell responses. The primary study outcome is to measure and compare responses after vaccination with RZV depending on the type and degree of immunosuppression using gE-specific antibody detection assays. As a secondary outcome, first, the gE-specific CD4(+) T cell response of the three cohorts will be compared and, second, the gE-VZV antibody levels will be compared with the severity of possible vaccination reactions. The tertiary outcome is a potential association between VZV immune responses and clinical protection against shingles.Ethics and dissemination Ethical approval was issued on 07/11/2022 by the Ethics Committee Essen, Germany (number 22-10805-BO). Findings will be published in peer-reviewed open-access journals and presented at local, national and international conferences.