Evaluation of safety, humoral immune response and faecal shedding in horses inoculated with a modified-live bovine coronavirus vaccination.
Authors: Prutton J S W, Barnum S, Pusterla N
Journal: Equine veterinary education
Summary
# Editorial Summary With equine coronavirus continuing to emerge as a significant enteric pathogen (morbidity 10–83%, mortality 7–27%), researchers explored whether a licensed modified-live bovine coronavirus vaccine might offer cross-protection, given the absence of an equine-specific vaccine. Twelve healthy adult horses received two doses of the BCoV vaccine at three-week intervals via oral, intranasal or intrarectal routes, with clinical monitoring, viral shedding assessed by qPCR in nasal secretions and faeces, and antibody responses measured serologically; two unvaccinated horses served as sentinels. The vaccine proved safe across all routes, with only transient faecal changes noted in seven vaccinates and one control animal, whilst viral shedding was minimal—two horses after the first dose and one after the second showed qPCR-positive nasal secretions following intranasal vaccination, but none shed virus in faeces. Perhaps most significantly, only 27% of vaccinated horses (three of eleven) mounted a detectable BCoV-specific antibody response, with seroconversion occurring following either the first or second dose depending on route of administration. These findings suggest the BCoV vaccine is well tolerated in horses with negligible environmental contamination risk, yet the modest immunogenic response raises questions about protective efficacy that warrant further investigation before recommending this strategy for disease prevention in equine populations.
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Practical Takeaways
- •Modified-live BCoV vaccine appears safe for use in horses via multiple routes (oral, intranasal, intrarectal) with minimal adverse effects
- •Cross-protective immune response from bovine vaccine in horses is poor, with only 3 of 12 horses developing detectable antibodies
- •Low seroconversion rate suggests modified-live BCoV vaccine is unlikely to provide effective protection against equine coronavirus without further development
Key Findings
- •Modified-live BCoV vaccine was safe in horses with only transient, self-limiting faecal changes observed in 7 of 12 vaccinated horses
- •Minimal viral shedding occurred post-vaccination: 2 horses shed BCoV nasally after first dose and 1 after second dose; no faecal shedding detected
- •Only 27% of vaccinated horses (3 of 12) seroconverted to BCoV-specific antibodies following two vaccine doses