Safety and immunogenicity of an adjuvanted recombinant spike protein‐based severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) vaccine, SpikeVet™, in selected Carnivora, Primates and Artiodactyla in Australian zoos

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) can infect a broad range of animal species and has been associated with severe disease in some taxa. Few studies have evaluated optimal strategies to mitigate the risk to susceptible zoo animals. This study evaluated the safety and immunogenicity of a protein‐based veterinary SARS‐CoV‐2 vaccine (SpikeVet™) in zoo animals. Two to three doses of SpikeVet™ were administered intramuscularly or subcutaneously 3–4 weeks apart to 354 zoo animals representing 38 species. SpikeVet™ was very well tolerated across all species. Minor adverse effects were observed in 1.69% of animals vaccinated, or 1.04% of vaccine doses administered. Preliminary immunogenicity analyses in representative carnivores (meerkats, lions) and an artiodactylid (domestic goat) showed SpikeVet™‐immunized animals developed serum antibodies able to neutralize a range of SARS‐CoV‐2 variants, including the vaccine‐homologous Wuhan and Mu variants, as well as vaccine‐heterologous Omicron BA.2 and XBB.1 strains. Prior to vaccination, all eight lions were seropositive for Wuhan strain by surrogate viral neutralization testing, suggesting past infection with SARS‐CoV‐2 or cross‐reactive antibodies generated by another closely related coronavirus. These results from a range of zoo species support the ongoing development of SpikeVet™ as a safe and effective veterinary SARS‐CoV‐2 vaccine.

Clinical development of SpikoGen®, an Advax-CpG55.2 adjuvanted recombinant spike protein vaccine

“…Given its strong safety and efficacy profile in multiple species, SpikoGen® technology was selected by the Australian Zoos Association to immunize susceptible zoo species including lions, tigers, and non-human primates against COVID-19. 52 A bivalent version called SpikeVet™ that contained Wuhan and Mu spike protein CD with Advax-CpG55.2 adjuvant was administered as a course of two or three immunizations, with 867 vaccine doses being administered to 354 zoo animals, drawn from 38 species in total, thereby potentially representing perhaps the largest OneHealth pandemic vaccine studies ever attempted. SpikeVet™ was found to have an excellent safety profile in the zoo species tested with the low rate of minor adverse effects and the absence of major adverse events.…”