No they don't. You can get tetanus vaccines that last 2 or 3 years for horses. Don't you think it odd that human vaccine lasts 10yrs? Or am I the only one that thinks we're being conned?
This is what my vet recommended as well, but as we hack out on the forest alot and sometimes the NF ponies come down with different things we've always kept them on the yearly jab. As it's not worth the risk (but that's just my opinion) if I lived somewhere that didnt have loose ponies where I hack out or I was only on bridleways then I'd do the 18month rule as wellIf only using a flu vaccine for health and you never compete or hack near other horses then my vet has advised you could go every 18 months. We used to do that with my old Shetland who died recently. He never went off the yard but he was old and more vulnerable to infections. As some of the other ponies do go out and might have brought infections back and given them to him we kept his vaccination current for health but not for competition.