MVA was developed to be a safe smallpox vaccine by further attenuating the standard smallpox vaccine during serial passage in chicken embryos. The MVA component of the GeoVax vaccine is used to deliver genes expressing non-infectious forms of the three major proteins of HIV: Gag, Pol, and Env. This vaccine has been used as a single component vaccine with MVA priming and boosting, or as a two component vaccine with DNA priming and MVA boosting, to protect monkeys against AIDS. The GeoVax MVA vaccine also protects monkeys against smallpox (monkeypox). Thus, it could be a dual-purpose vaccine for both HIV and smallpox. MVA has been used safely in over 120,000 humans including immunocompromised individuals .
an attenuated (non-pathogenic) strain of vaccinia (pox) virus, incapable of replication in human. MVA was administered to more than 120,000 individuals towards the end of the smallpox eradication campaign without any significant adverse effects.