ugh! So I was vaccinating one of my horses today for Rhino/flu and he jerked at the wrong time causing half of the vaccine to run down his neck, Im positive that I got half of it into him. This is his annual booster.  Anybody know if it's still effective or do I need to get another one? I plan to ask my vet tomorrow but am curious if anybody out there would know? Thanks!

I would definitely ask the vet but personally, I wouldn’t worry about it if you’re sure you got half in. If it was a SS/WNV/TET I’d probably re do it.