The immunogenicity of the MV1-F4 candidate vaccine was not investigated in detail in the current study, as our study was primarely designed to assess the toxicology, biodistribution and shedding profiles of the candidate vaccine. However, immune responses directed against the F4 transgene were characterized in a separate study using the same animal model (MV-seronegative cynomolgus macaques). In the latter study, the MV1-F4 candidate vaccine was shown to induce F4specific CD4 + and CD8 + T cell responses, as well as antibody responses to F4 (manuscript in preparation).