American researchers have developed a platform that can deliver single-dose vaccines, which fully protect against emerging infectious diseases such as Zika, Ebola and Lassa fever.
The technology developed by GeoVax, an Atlanta-based clinical-stage biotechnology company, was presented on Sunday at ASM Microbe, the ongoing annual meeting of the American Society for Microbiology.
It is "well suited for use against a wide range of biological threats and amenable to rapid, large-scale production," said Rahul Basu, scientist at GeoVax and lead author on the study.
The vaccines are suitable for repeated use, stable at refrigerator temperatures or lyophilized for non-cold chain needle-free application, and amenable to rapid and affordable scale-up for use in both epidemic response and routine vaccination, according to Basu.
In proof-of-concept studies, the researchers tested three independent vaccines against three different families of viruses. Each vaccine demonstrated full protection after a single dose, using various lethal challenge models.
For the Zika vaccine, a single inoculation of MVA-Zika vaccine in normal mice provided 100 percent protection against a lethal challenge dose of a neurovirulent Zika virus delivered directly into the brain.
A single inoculation of MVA-VLP-Ebola vaccine candidate provided full protection in a rhesus monkey lethal challenge model.
And a single inoculation of MVA-VLP-LASV vaccine protected mice against a lethal Lassa fever delivered directly into the brain.
"To demonstrate a broad utility of the platform, we developed prophylactic and therapeutic vaccines for other infectious diseases as well as cancer," said Basu.
These included preventive and therapeutic vaccines for HIV (already in advanced clinical trials), preventive vaccines for Marburg, Sudan and Malaria, all with major epidemic potential with high human lethality, as well as therapeutic vaccines for chronic hepatitis B infections and tumor-associated antigen-based cancer vaccines.