A vaccine against Lassa virus would be highly significant in preventing outbreaks which are both naturally occurring or the result of bioterrorist activity. Lassa virus has been identified as the cause of outbreaks of hemorrhagic fever for which there is no effective treatment or cure. Therefore, vaccine studies are critically important for protection against infection. We developed a highly effective vaccine strategy for Ebola virus infection in non-human primates. Our laboratory has demonstrated that protective immunity to Ebola can be generated with a single inoculation of an adenoviral vector vaccine, a result with significant implications for conducting enhanced ring vaccination during an Ebola outbreak. We aim to use a similar strategy for Lassa.