Pre-clinical data Using this BCG prime-MVA85A boost in BALB/c mice induces higher levels of both antigen specific interferon-gamma (IFN-γ) secreting CD4 T and CD8+ T cells and higher levels of protection than after BCG alone. This regime has now been further evaluated in the more sensitive guinea pig aerosol challenge model with very encouraging results. Guinea pigs vaccinated with BCG, followed by MVA85A, and then further boosted with a second recombinant viral vector, fowlpox, expressing antigen 85A (FP85A) showed significantly greater protection against challenge than guinea pigs vaccinated with BCG alone. This regime is also immunogenic and protective in rhesus macaques