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

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.