Described herein are i-DNA™ vectors and vaccines and methods for using the same. The i-DNA™ generates live attenuated vaccines in eukaryotic cells in vitro or in vivo for pathogenic RNA viruses, particularly chikungunya virus (CHIKV). When iDNA is injected into the vaccine recipient, RNA of live attenuated virus is generated by in vivo transcription in the recipient's tissues. This initiates production of progeny attenuated viruses in the tissues of the vaccine recipient, as well as elicitation of an effective immune response protecting against wild-type, non-attenuated virus.