Equine influenza vaccination in the UK: Current practices may leave horses with suboptimal immunity.
Authors: Wilson Amie, Pinchbeck Gina, Dean Rachel, McGowan Catherine
Journal: Equine veterinary journal
Summary
# Equine Influenza Vaccination in the UK: Suboptimal Immunity Despite Current Practice Despite vaccination being fundamental to equine health, substantial variation exists in how UK veterinarians advise influenza immunisation protocols, with potentially significant consequences for herd immunity. Wilson and colleagues surveyed 304 equine practitioners and found that whilst most align recommendations with competition bodies (British Horseracing Authority 68.8%; Fédération Équestre Internationale 66.4%), only 7.7% actually follow manufacturer datasheets for the critical interval between second and third primary vaccinations—a worrying discrepancy that suggests horses may not achieve the antibody titres necessary for robust protection. The most common approach involves 6-monthly boosters for competition horses and annual vaccination for leisure animals, though these protocols vary considerably between practitioners. Compounding these inconsistencies, two-thirds of respondents encountered adverse events (transient reactions including stiffness, localised swelling and pyrexia being most prevalent), yet less than one-fifth reported cases to the Veterinary Medicines Directorate, hampering pharmacovigilance efforts. For practitioners advising on influenza protection, these findings highlight a critical gap between regulatory compliance and immunological adequacy—reconsidering booster intervals against datasheet recommendations, rather than relying solely on competition guidelines, may be necessary to ensure horses develop and maintain sufficient immunity whilst managing owner concerns around over-vaccination and cost.
Read the full abstract on PubMed
Practical Takeaways
- •Current UK vaccination practices may not provide optimal immunity despite compliance with competition rules—review your protocols against manufacturer datasheets to ensure proper spacing between vaccine doses
- •Most adverse vaccination reactions are transient (stiffness, swelling, lethargy, fever), but underreporting to authorities limits safety monitoring—consider reporting significant cases to improve surveillance data
- •Address owner vaccine hesitancy by discussing the balance between immunity requirements, competitive rules, and individual horse risk rather than adopting blanket vaccination schedules
Key Findings
- •Only 7.7% of surveyed UK veterinarians complied with vaccine manufacturer datasheet timeframes between second and third vaccinations
- •57% of respondents reported variation in booster frequency, most commonly 6-monthly for competition horses and annual for non-competition horses
- •66% of respondents encountered adverse vaccination events in the previous year (2,760 total events) but only 19.1% were reported to regulatory authorities
- •86.4% of respondents reported vaccine hesitancy from horse owners, primarily due to over-vaccination concerns, cost, and adverse event concerns