Analysis of herpes zoster cases in multiple sclerosis patients treated with disease-modifying drugs: insights from the EudraVigilance database.

Multiple sclerosis (MS) itself and disease modifying treatment (DMT) used in MS are risk factors of adverse herpes zoster (HZ) infection development. During HZ infection complications might develop, e.g. postherpetic neuralgia or optic neuritis, decreasing patients' quality of life. Data concerning HZ development in MS patients is limited. The authors aimed to assess the number of reports on adverse HZ development in MS patients treated with different DMTs. The EudraVigilance database was analyzed to identify HZ reports among all adverse event reports related to MS disease-modifying therapies from 2003 to 2024. Reporting odds ratios (RORs) for the drugs were calculated, and Fisher's exact test was used. When p < 0.05, results were concluded statistically significant. The authors identified 2,017 reports of HZ associated with MS DMTs. The highest ROR values were noted for fingolimod (4.09), cladribine (3.33), and alemtuzumab (2.27). The lowest ROR values were noted for glatiramer acetate (0.17), interferons ( 0.21) and teriflunomide (0.35). The study shows that some DMTs used in MS might significantly increase the risk of HZ development. While treating MS patient with DMTs the risk of adverse HZ should be evaluated. Vaccination against HZ should be recommended for patients to benefit the most from the available treatment.