Potency of a thermostabilised chimpanzee adenovirus Rift Valley Fever vaccine in cattle.
Dulal P., Wright D., Ashfield R., Hill AV., Charleston B., Warimwe GM.
Development of safe and efficacious vaccines whose potency is unaffected by long-term storage at ambient temperature would obviate major vaccine deployment hurdles and limit wastage associated with breaks in the vaccine cold chain. Here, we evaluated the immunogenicity of a novel chimpanzee adenovirus vectored Rift Valley Fever vaccine (ChAdOx1-GnGc) in cattle, following its thermostabilisation by slow desiccation on glass fiber membranes in the non-reducing sugars trehalose and sucrose. Thermostabilised ChAdOx1-GnGc vaccine stored for 6 months at 25, 37 or 45°C elicited comparable Rift Valley Fever virus neutralising antibody titres to those elicited by the 'cold chain' vaccine (stored at -80°C throughout) at the same dose, and these were within the range associated with protection against Rift Valley Fever in cattle. The results support the use of sugar-membrane thermostabilised vaccines in target livestock species.