Bastidas A, et al. - Through a phase 3, randomized, observer-blinded clinical trial of 1,846 patients who underwent autologous hematopoietic stem cell transplantation (HSCT), experts evaluated the effectiveness and adverse events associated with recombinant zoster vaccine in immunocompromised autologous HSCT recipients. Individuals randomly received 2 doses of either recombinant zoster vaccine (n=922) or placebo (n=924) given into the deltoid muscle. At least 1 herpes zoster event was verified in 49 vaccine and 135 placebo recipients resulting in 68.2% vaccine effectiveness during the 21-month median follow-up. Three out of 8 secondary endpoints showed decreases in postherpetic neuralgia incidence and of other herpes zoster-related complications and in the length of severe worst herpes zoster-associated pain. In 86% and 10% of vaccine and of placebo recipients, respectively, reported injection site reactions; pain was the most frequently seen in 84% of vaccine recipients. At all time points, unsolicited and serious adverse events, possibly immune-mediated diseases, and underlying disease relapses were comparable among groups. A 2-dose course of recombinant zoster vaccine vs placebo significantly lowered herpes zoster incidence over a median follow-up of 21 months in adults who underwent autologous HSCT.