Objectives
The primary objectives were (1) to demonstrate noninferiority in terms of humoral immunogenicity of 2 doses of RZV when RZV1 was coadministered with an mRNA-1273 booster dose compared to RZV1 administered 2 weeks after mRNA-1273; and (2) to demonstrate noninferiority in terms of humoral immunogenicity of a booster dose of mRNA-1273 when coadministered with RZV1 compared to its administration 2 weeks prior to RZV1. Secondary objectives were to characterize the immune responses to RZV and mRNA-1273 and to evaluate safety and reactogenicity of the study vaccines, and are provided in the 