Available for licensing from the NIH are gene constructs that express immunogenic proteins based on viral genes that have been optimized for expression in mammalian cells. Using vaccine vectors expressing respiratory syncytial virus (RSV) proteins from the optimized genes, this technology was shown to result in a potent RSV-specific cellular immune responses with favorable phenotypic patterns. This technology was shown to generate a superior immune (both humoral and cellular) response when utilized as part of a heterologous vector prime-boost regimen. Such optimized genes could be an important component of an effective RSV vaccine. Further, this optimization could have possible application of to other viral genes and their respective vaccines.