Although the interpretation of the safety data are subject to limitations resulting from the need to maintain participant-level study blinding, at present, no safety concerns have been raised by either the independent monitors who have critically reviewed and analyzed the unblinded safety data during the course of the study or the sponsor's firewall team, who reviewed and confirmed the results presented here. Exacerbation or triggering of immune-mediated diseases in susceptible persons is a hypothetical concern for vaccines containing new adjuvants such as AS01B because of their immunostimulatory effects.16,34,35 Through careful monitoring during the course of the study, we found no evidence that immune-mediated diseases occurred more frequently among HZ/su recipients than among placebo recipients. The safety of HZ/su will continue to be monitored in the ongoing ZOE-50 and ZOE-70 studies.