And The Vet Said...

Vaccine Reactions

Since I began practicing veterinary medicine the effectiveness and delivery methods of vaccines have improved dramatically. Today's vaccines are very safe, effective, and rarely cause reactions when administered properly and with good aseptic technique.

Some of the most severe reactions that occur are when owners inadvertently inject vaccines designed to be given intra-nasal (in the nose), into the muscle by mistake. Several years ago I had a client do just that. She purchased an intra-nasal strangles vaccine and she injected it into the horse's neck muscle. When she realized what she had done she called me in a panic. I contacted the pharmaceutical company for a consultation since this was a relatively new vaccine on the market. The veterinarian on staff at the pharmaceutical company instructed me to infiltrate the injection area with Dexamethasone and Penicillin. I did this procedure, followed by 5 additional days of penicillin injections and topical DMSO therapy to the area. The swelling on the neck completely resolved and no abscess resulted from the injection.

Recently I vaccinated 10 horses with routine fall vaccinations. One horse of the 10 reacted to the vaccination. The reaction was to a common vaccine that I rarely see any reactions to:

The vaccine was given on Day 1
Day 2 AM the owner noticed the horse was lethargic with a sore neck but no visible swelling noted, the temperature was 103, antibiotics, anti-inflammatory agents, and topical DMSO was administered.
Day 2 PM the temperature was 105, still no visible swelling noted, antibiotics were expanded and anti-inflammatory agents and DMSO were continued.
Day 3 AM the temperature was normal, still no visible swelling noted, the same treatment was continued.
Day 3 PM the temperature was normal, the horse had an obvious 4x10 inch swelling on the neck at the site of injection. I infiltrated the swelling with Dexamethasone and Penicillin. The other antibiotics, anti-inflammatory agents and topical DMSO were also continued.
Day 4 AM the temperature was normal and the swelling on the neck was down by 50%.
Day 7 The inflammation was completely resolved.

In the future if I am faced with any vaccine reactions that do not respond to topical DMSO, oral anti-inflammatory agents and an obvious swelling is noted at the injection site I will use the treatment of infiltrating the area with Dexamethasone and Penicillin within a short time after noting the pronounced inflammation.

This was an interested case and I encourage anyone facing this situation to contact your veterinarian and have your horse treated before an abscess results. Occasionally horses will experience vaccination reactions for no apparent reason. I also encourage those that perform their own vaccinations to apply aseptic technique and read all labels thoroughly to minimize the chance that a reaction may occur.