How often should my horse get a west nile shot?

If your horse had one last year, it is suggested that a horse should have a yearly booster shot. I Give mine the WNV booster when we draw for the coggins and give the other vaccs we use each spring. If it's been more than a year, you should consult the vet to be sure the horse will not need the 2 shot series to renew it's resistance to the WNV.