Nanoparticle-encased vaccines can fend off lethal pathogens in animals, and could allow for a swift response to disease outbreaks.

Vaccines made from live virus can elicit long-lasting immunity, but most are slow and laborious to make. Daniel Anderson at the Massachusetts Institute of Technology in Cambridge and his colleagues instead made a fully synthetic vaccine by encasing antigen RNA in a modified-polymer nanoparticle that protected the RNA from degradation.

Single injections of such vaccines against the Ebola virus and the influenza virus, as well as the parasite Toxoplasma gondii, were sufficient to generate immune responses in mice and to protect the animals against otherwise lethal doses of the pathogens.

Proc. Natl Acad. Sci. USA http://doi.org/bk45 (2016).