Background: Patients with rheumatic diseases (RMDs) are at increased risk of herpes zoster (HZ), particularly when receiving immunosuppressive treatment. While recombinant zoster vaccine (RZV) has shown high effectiveness in the general population, evidence in rheumatologic patients remain limited due to their exclusion from pivotal trials. Objectives: To evaluate the effectiveness of RZV and to collect additional safety data in a heterogeneous cohort of rheumatologic patients, compared with a control cohort from the general population. Methods: We conducted a retrospective study including 179 adults who received two intramuscular doses of RZV between January 2021 and June 2025. The cohort included 114 patients with RMDs and 65 individuals from the general population. Effectiveness was defined as the ability to prevent HZ reactivation while safety concerns were recorded as any adverse event temporally associated with the vaccination. Results: We observed a statistically significant reduction in terms of VZV relapses following vaccination (p < 0.001). Among patients diagnosed with RMDs, only one case of HZ recurrence was observed 14 weeks after vaccination, with no significant difference compared to general care patients. One patient experienced a disease flare requiring glucocorticosteroids. RZV demonstrated a favourable safety profile, with minor adverse events (fever, injection-site reactions, headache and myalgia) reported in 17.5% of patients after the first dose and 21.5% after the second. No significant association was observed between adverse events and advanced immunosuppressive therapy. Conclusions: RZV displayed an effective and reassuring safety profile in a heterogeneous cohort of patients affected by RMDs, irrespective of the diagnosis and the ongoing therapy. This supports the broader use of RZV as a safe and valuable preventive strategy in patients with RMDs.

Background/Objectives: Psoriatic disease (PsD) is a chronic, systemic inflammatory disorder characterized by a wide spectrum of clinical manifestations extending beyond skin and joint involvement. Increasing evidence suggests a relevant role of the gut microbiota in the pathogenesis of psoriatic arthritis (PsA), although a clear causal relationship remains to be fully established. The aim of this review is to summarize current evidence on the role of the gut microbiome in PsD, with a focus on immune modulation, disease pathogenesis and potential therapeutic implications. Methods: A narrative review of the literature was conducted, focusing on studies investigating gut microbiota composition, dysbiosis patterns, and microbiome-related mechanisms in PsD and PsA, as well as emerging microbiota-targeted interventions. Results: Recent advances in high-throughput sequencing technologies have identified distinct microbial signatures associated with PsA onset and progression. Dysbiosis appears to influence immune system regulation, contributing to systemic inflammation through mechanisms involving intestinal barrier dysfunction and immune activation. Patients with PsA exhibit specific alterations in gut microbial composition compared to healthy controls. Emerging therapeutic strategies targeting the microbiota—including dietary interventions, probiotics, and fecal microbiota transplantation—show potential as adjunctive approaches in disease management, although clinical evidence remains limited. Conclusions: The gut microbiome represents a promising area of research in PsD, offering novel insights into disease mechanisms and potential therapeutic targets. Further studies are needed to clarify causal relationships and to define the clinical applicability of microbiota-based interventions.