The Real-World Study of Immunogenicity and Safety of the Adjuvant Recombinant Vaccine against Varicella Zoster Virus in Patients with Immune-Mediated Inflammatory Diseases Treated with Janus Kinase Inhibitors

Background. The risk of herpes zoster reactivation is increased in immunocompromised patients, especially in those with immune-mediated inflammatory diseases (IMIDs) on Janus kinase inhibitor (JAKi) treatment. The recombinant subunit herpes zoster vaccine (RZV) is a non-live vaccine, recently approved for this subgroup of patients, which shows high rates of vaccine effectiveness, with few adverse effects reported in clinical trials. Purpose. The aim of this real-world study was to determine the immunogenicity and safety of RZV in IMID patients on JAKi treatment. Methods. The increase in the concentration of anti-gE antibody for varicella zoster virus post-vaccination, compared to the pre-vaccination concentration, was analyzed to test the humoral immune response. Adverse effects after the first and second vaccine doses were registered. Results. In total, 49 patients were analyzed, and a fourfold increase in antibody concentration was achieved in almost 40% of subjects, with only one serious local adverse effect. Discussion. The resulting immunogenicity was lower than that observed in clinical trials, probably due to the presence of immune disease and immunosuppressive treatment, and to the fact that this was a real-world study. No differences in response according to age, previous virus zoster reactivation, or concomitant treatments were found. Conclusions. RZV was well tolerated and reached the immune response objective in 40% of patients. These results reinforce the importance of including RZV vaccination for immunosuppressed patients. Real-world studies regarding vaccine effectiveness are still needed in order to gain a full understanding of the response to RZV in this group of patients.