Ohfuji S, et al. - In this prospective cohort study, researchers examined the safety of live attenuated varicella-zoster vaccine in 1200 healthy adults and in 300 patients with underlying illnesses such as malignancy, diabetes mellitus, autoimmune diseases, and renal diseases was conducted. They observed 2 severe adverse events (SAEs) (bone fracture and acute cholecystitis) among healthy adults and 1 SAE (disseminated mycobacteriosis) among patients with underlying illnesses during the follow-up period, although none of them was related to vaccine. In both groups, the most frequent adverse events (AEs) were injection-site AEs (ie, 41 and 39%) and systemic AEs were observed in 4%. Healthy adults with a history of herpes zoster more frequently reported injection-site AEs than those without a history of herpes zoster (53% vs 39%). Outcomes thus suggest freeze-dried, live attenuated varicella-zoster vaccine as safe even in patients with underlying illnesses.