Vaccinia recombinant expressing Lassa-virus internal nucleocapsid protein protects guineapigs against Lassa fever.

The Lister strain of vaccinia virus was used to construct a recombinant that expressed the nucleocapsid gene of Lassa virus. Guineapigs immunised with the recombinant virus were protected against challenge with Lassa virus, whereas control animals showed the usual disease course, including pyrexia, anorexia, viraemia, and death. These data indicate not only that protective immunity to Lassa fever can be evoked by an experimental vaccine, but also that this response can be mediated by an internal protein component of the virus.