mRNA Vaccine Tested in Rodents Protects Against Three Ebola Strains

A new mRNA vaccine tested in rodents generated immune responses against three orthoebolaviruses: Zaire, Sudan, and Bundibugyo. The vaccine encodes the glycoproteins from each virus plus a shared nucleoprotein, all packaged in a single lipid nanoparticle.

Mice that received the vaccine showed complete protection against Zaire and Sudan viruses and strong protection against Bundibugyo virus. Hamsters given the same vaccine were fully protected from Sudan virus.

Health officials in the Democratic Republic of the Congo reported more than 600 suspected Bundibugyo infections as of 21 May. Two confirmed cases have also been recorded in Uganda, prompting the World Health Organization to declare a public health emergency of international concern. No licensed vaccines exist for Bundibugyo or Sudan viruses. Two vaccines are approved only for the Zaire strain.

Yao and colleagues at the Wuhan Institute of Virology wrote that a broad-spectrum vaccine could help mitigate outbreaks caused by multiple orthoebolaviruses. They noted the formulation has so far been tested only in rodents. Robert Cross of the University of Texas Medical Branch stated that non-human primate studies are the standard for predicting human efficacy.

Adrian Esterman of Adelaide University said further animal work, manufacturing development, and safety testing would typically take several years before human trials could begin. 1073/pnas.