Equine influenza vaccination is one of the most effective preventive welfare measures for horses in social contact, and vaccine development continues to improve protection against evolving strains.
Equine influenza vaccination is a collective welfare responsibility because outbreaks propagate through populations of unvaccinated horses, causing welfare harm that extends far beyond individual unprotected animals. Vaccination gaps in equine populations create opportunities for outbreak amplification that affects even well-vaccinated individuals whose immunity is waning at the time of exposure. Competition and movement regulations that require vaccination compliance are therefore welfare protection measures for the equine population as well as individual animal protection. The development of updated vaccine strains that match circulating influenza clades maintains efficacy that requires ongoing surveillance and vaccine development investment by pharmaceutical companies working in equine health.