Vaccinosis? Should I be worried? Ask the Vet.

Every year I have to vaccinate my horse for a variety of things. In North America the list of recommended vaccinations is quite long.

1.       Flu and Rhinopneumonitis ( Equine Herpesvirus)

2.       Tetanus

3.       Rabies

4.       Eastern Encephalitis (EEE)

5.       Western Encephalitis (WEE)

6.       West Nile Virus (WNV)

7.       Potomac Fever

8.       Strangles

The last two, Potomac and Strangles are only recommended in areas where there have been outbreaks of these two diseases, but the rest are recommended on an annual basis. Furthermore if your horse has an FEI (International Equestrian Federation) passport and competes in shows that come under the jurisdiction of the FEI you must have a flu vaccination every six months and it must be stamped in the passport or the horse will not be allowed to compete.

It’s a lot of shots. Every year, year after year. In humans, there has been considerable controversy about childhood vaccinations and there is also some controversy in the horse world as well.  There is the belief that the over vaccination of horses can result in a condition known as Vaccinosis. What is that? Should I be worried?

To answer those questions, I spoke with veterinarian Robert Remlinger. 

“Vaccinosis is a short term or long term reaction to vaccine,” he told me. “It has not been clinically proven or disproven and some dismiss it as “hogwash”. But the longer I practice the more I see it.”

He explained to me that the immune system is set up to react over time and repeated stimulation of the immune system can produce unwanted effects in some horses. These effects are usually autoimmune responses such as heaves (a chronic respiratory problem or COPD )or laminitis ( hoof inflammation) and skin disorders.  Not all horses will have this kind of response and many seem to tolerate vaccines well but for those who are sensitive  a very moderate approach should be taken.

“I like to assess the individual horse,” Dr. Remlinger said.” Where is the horse living? Is there an outbreak of Potomac or Strangles in the area? How many horses are kept at the stable? Do they travel? Do other horses come in for shows? From there I can decide what vaccines are needed for the horse. I like to take a moderate approach even with a healthy horse.”

What is a moderate approach? Well, I happen to have a horse that reacts to vaccines and I was told this when I first got him. I was told that his neck would swell and be stiff and sore after vaccination.  To Dr. Remlinger this is a Red Flag. My horse, Biasini, is one that needs the moderate approach and so we split up all of the vaccines he gets.  As he travels to Florida in the winter and goes to shows and has an FEI passport he needs several vaccines.  He has the flu rhino twice a year. He gets WEE and EEE, WNV all before he goes to Florida as those are insect born diseases and more likely to be in Florida than in Canada.  He will also get rabies and tetanus annually.   Dr. Remlinger advises spreading out these vaccinations and leaving at least a week in between them to allow his immune system to settle down and also to observe any reactions.  We also give him an injection of an anti inflammatory to alleviate any soreness he may have from the vaccination. So far, this approach has worked well.

What about a horse that already has some autoimmune problems such as respiratory issues? “I try to treat the horse to suppress the autoimmune response.” Dr. Remlinger replied. “The response has a memory and over time the response will increase in response to the stimuli. The vaccine affects the immune system at its’ core and primes it for bigger reactions in the future. So, if the horse already has heaves, for example, I would be extremely cautious about vaccinating.”

Dr. Remlinger believes in vaccinating horses and says the vaccines can be effective although not 100%.

A horse may come into the stable and be a Trojan Horse for a disease, with no symptoms but carrying it and infecting others. So, good biosecurity is recommended. Also, viruses are constantly evolving. Look at the flu virus in humans; every year it is a bit different and the annual flu vaccine may or may not protect you from the flu.

“Horses are the most over vaccinated species on the planet. “Dr. Remlinger told me. “Small animals such as dogs can be tested for a titre with a blood test and from that they have been able to develop guidelines on how frequently dogs need to be vaccinated. In an ideal world, we would get blood samples from horses, find the titre and vaccinate according to what was needed. But no one will fund a ten-year study on horses to find out what titre is sufficient in their blood to be effective. So, I believe in studying each horse and vaccinating with moderation depending on what that horse’s life entails. I also want horse owners to let me know if there is any reaction to a vaccine. Even if it is just a bit of a sore neck I want to know. I want to know how the horse reacted to the vaccine.”

Dr. Remlinger told me there are all sorts of horror stories of things like a two-headed foal being born after the mare was vaccinated for West Nile Virus. He says that there is a huge spectrum of reactions to vaccines but that story is not likely to be the result of a vaccine.

“Some horses will have problems over time with vaccinations. Are there risk factors in place? If yes, then proceed accordingly.”

His recommendations:

1.       Vaccinate for realistic risks with each horse.

2.       Split the vaccines up over several vaccinations.

3.       Report any reactions even small ones and be specific about what happened. Best to deal with it right away.

4.       Remember that in the short term a reaction is not a problem but over time with repeated hits on the immune system it can become a bigger problem.

So, that is the answer to my question on Vaccinosis. I must be cautious with my horse Biasini because he has a history of reacting to vaccines. With the vaccinations being split up there have been no problems and he is an otherwise very healthy horse. Finally, I would say it is important to speak with your vet and see what he or she recommends. I would not advise going to the internet as it can be a minefield of misinformation and horror stories. Be aware of what is going on in your location or the locations you go to for shows or travel, consult with your vet and observe any reactions after vaccines and report them to your vet.