Feasibility and safety of recombinant zoster vaccination in patients undergoing active cancer treatments: A real-world single-center experience.

Patients with solid tumors receiving systemic anticancer therapy face an increased risk of herpes zoster (HZ), a complication that can delay or disrupt ongoing oncologic treatments. Although the recombinant zoster vaccine (RZV) is recommended for immunocompromised adults, real-world data on its implementation and tolerability during active cancer treatment settings remain limited. We conducted a retrospective, single-center observational study at the Oncology Department of the "G. Martino" University Hospital, Messina, Italy. Between July 2022 and January 2025, the standard two-dose RZV schedule was systematically offered to adult patients with solid tumors who were receiving or scheduled to start systemic therapies. Endpoints included the operational feasibility of vaccination during oncologic care, safety, and HZ occurrence during follow-up. Overall, 42 patients received at least one RZV dose, and 37 (88.1%) completed the two-dose schedule. Patients were receiving different systemic anticancer treatments, mainly chemotherapy (59.5%), followed by chemo-immunotherapy and immunotherapy. RZV showed a favorable safety profile. Injection-site pain was the most frequently reported local adverse event, while systemic reactions, including fever and headache, were mild and transient. No severe vaccine-related adverse events or delays in oncologic treatment were observed. After a median follow-up of 11.5 months, no clinically documented HZ episodes occurred, although this finding should be interpreted descriptively given the limited sample size. Our experience suggests that integrating RZV into routine outpatient oncology workflows is feasible and well tolerated in patients undergoing active systemic treatments.