There’s something a bit mystical about vaccination. We inject an antigenic material from a tiny plastic cylinder into our horses’ necks and it triggers reactions at the cellular level that prepare their immune systems to fight bugs. So when they encounter another horse that’s shedding virus or bacteria and that horse coughs, sneezes, or smears snot on a common surface, our vaccinated horses are less likely to get sick. Or, if they do become infected, the clinical signs won’t be as severe as they would be if they hadn’t been vaccinated. Thompson and Brian Turner

I’ve observed that scheduling vaccinations is like clockwork for most of our readers—it’s simply what we do, especially if we haul to places where groups of horses congregate or if we live in places with mosquitoes or other disease vectors (the latter applying to pretty much all of us).

But over the years I’ve also noticed a few other tendencies: First, when times are tight, owners sometimes decide those few milliliters of antigen-containing fluid, coupled with a fee from a veterinarian’s farm call, are easy budget items to skip. Also, we tend not to think about disease until we’re faced with it.

These scenarios feed each other. We see fewer cases of a disease. We assume it isn’t circulating. We want to save money, so we skip vaccinating. Then we see a spike in disease. Every few years veterinarians, in university hospitals and ambulatory practices alike, call me, alarmed about upticks in disease cases, and ask me and my team to remind owners to remain vigilant and keep their horses’ vaccinations current.

I can’t predict where a disease-laden mosquito will snack, and encephalitis isn’t fun for anybody

There are a few other reasons why I will stay on a vet-directed vaccination course with the next horse I buy, based on what I’ve learned writing and editing stories:

Used in TH Video Portal. Chromeless, 16:9
  • Rabies, for one, is ugly. I’ve seen terrifying footage of infected end-stage horses and heard vets tell stories about tracking down every person inadvertently exposed to a case (for post-exposure prophylaxis). This and other debilitating infections are easily preventable.
  • I can’t predict where a disease-laden mosquito will snack, and encephalitis isn’t fun for anybody.
  • As far as transmissible diseases, I can’t look at a horse and know whether it’s shedding. And my own biosecurity measures can only go so far to protect my horse.
  • I’ve reported on outbreaks in naive horse populations and seen vaccination help resolve them.
  • The variables of individual immune system response, vaccine handling, etc. mean vaccines can’t be 100% effective, but risk-benefit analyses tell me that they still give our horses the best chance at staying well.

I don’t completely understand the intricacies of equine immune response, so I choose to trust researchers who have dedicated their careers to studying it. Their science-based guidelines are designed with equine welfare in mind. You’ll read more how to vaccinate your horses throughout the May issue of The Horse: Your Guide To Equine Health Care, along with other preventive care topics. The cover story on vaccinations for all ages is online, but you'll need to pick up a single copy or subscribe to see the rest.

 How do you make decisions about vaccinating your horses? 

This column first appeared in the May 2014 issue of The Horse.