I just had the vet do three of my horses with the combo EWT/WN shot yesterday....this is the first time I have done combo shots in many years (last time I had reactions, but it was a combo with flu/rhino). So far, so good...no problems with the shots yesterday. It seems the shots I see reactions with are the flu/rhino shots (and the vet did them for me at the time). Out of 20 horses that got the flu/rhino combo shot a few years ago, 10 of them had high fevers, disorientation, staggering and could not lift their heads (shots were in the neck) for almost a WEEK! Guess what? I don't even vaccinate for flu/rhino now since I don't have much exposure. It certainly is easier to give only one shot, though. I usually will give them at two-week intervals (the ones I can get myself), but I always have the vet give the initial shots to weanlings who have never been vaccinated before, just in case they do have a reaction (that's the reason for my vet doing the shots for me yesterday). I have not previously been able to buy the West Nile separately myself, but I think it is available now at equine supply stores/online.