Hemagglutinin inhibition antibody responses to commercial equine influenza vaccines in vaccinated horses.

< 0.05 and all groups had a significant increase in antibody titers pre- and post-administration of the first dose. In contrast, there was no significant difference between day 30 titers and titers at subsequent time points, regardless of protocol. We concluded that administration of various commercial influenza vaccines containing a different sub-lineage clade stimulated equivalent HI antibody titers after 1 booster vaccination.