Ask the Vet: Immunization

Question: My current boarding barn requires vaccination for Strangles. My horse has been exposed to Strangles several years ago at a former boarding barn, but did not get sick. My veterinarian recommends using the killed virus vaccination if I absolutely must get it. What do you think?

Answer: This is an excellent question because you are certainly not alone in this situation. There are definitely some options and you may need to discuss your situation with the boarding barn management. Since the horse did not contract Strangles, but was possibly exposed, I would recommend to test your horse’s titers or level of immunity to Strangles. If the titers or levels of antibodies are high, I would not vaccinate and show the proof of titer to your boarding barn manager. If he or she has low titers then I would consider vaccinating with a killed or modified live vaccine (MLV). The killed vaccine is intramuscular (IM) and can cause muscle soreness, swelling, or even abscesses. The MLV is an intranasal vaccine and protects the mucosa in the upper airway. The side effects I see to the MLV is occasionally a runny nose from the nostril it was administered in.

Question: Is it still recommended to vaccinate for all three (3) forms of equine encephalitis (Eastern, Western and Venezuelan)? I notice a lot of the combo shots but only include two out of three (Eastern and Western).

Answer: What a good question! I too have also noticed the change in the vaccine combinations that are available. At this point in time, the American Association of Equine Practitioners recommends the Eastern Equine Encephalitis, and Western Equine Encephalitis as part of the core vaccines. I would say that the Venezuelan Equine Encephalitis would be a risk based vaccine. If the area you keep your horse in has had an outbreak, then I would recommend to vaccinate. Fortunately in the US, VEE has not been diagnosed for more than 35 years. The last cases were most notable in Florida. At this point, I would not vaccinate for VEE, but definitely EEE and WEE.

Question: There is controversy about “over vaccinating” humans, pets and horses. What is your opinion on this topic?

Answer: This is a very timely question. I believe that over vaccination can be an issue, however if your horse is in an environment that increases his or her exposure to disease, I recommend that you vaccinate. I recommend vaccinations based on the AAEP’s core vaccines, which include annual rabies, Eastern and Western encephalitis, West Nile Virus and Tetanus. If you travel with your horse or keep your horse at a barn where there is a lot of horse traffic, I would strongly recommend that you also vaccinate for Equine Influenza (flu) and Equine Herpesvirus (a.k.a. rhino). You may also consult with your veterinarian regarding vaccinating for Strangles. I recommend that you vaccinate your horse based on his or her risk. For example, I practice in Georgia where with our mild winters and wet springs, I recommend semi-annual vaccines for EEE (eastern equine encephalitis), WEE (Western equine encephalitis), and WNV (West Nile Virus). I would recommend that you discuss what vaccines are appropriate for your horse with your veterinarian.