Disclosed herein are nucleotide sequences which encode a plurality of structural proteins, except the capsid, of an equine encephalitis virus, wherein the nucleotide sequence is codon-optimized for mammalian expression. The nucleotide sequences are codon-optimized for expression in humans. As disclosed herein, the nucleotide sequences confer protection against Venezuelan equine encephalitis virus (VEEV), western equine encephalitis virus (WEEV), and/or eastern equine encephalitis virus (EEEV).
