Vaccination guidelines change from year to year. Every year research brings out new information on products, timing of vaccinations, and routes of administration.  It becomes more challenging to recommend when your horses should be vaccinated and with what.

When deciding what vaccines are needed for your horse, you need to know where your horse lives, where or if they will be traveling, how often they may be around other horses, and if they are pregnant.  When taking these into consideration we usually divide vaccinations into essential, highly recommended, and questionable.  This article deals primarily with horses in the Northwest Washington and Oregon region.  If your horses live in another part of the country, I would recommend that you talk with your local veterinarian for guidelines for that state.

Essential Vaccinations:         

For any horse, performance or backyard, Tetanus vaccination should be considered essential.  Horses are one of the higher risk animals for getting Tetanus. Tetanus is a Clostridial bacteria that lives in the soil and can gain entrance into the system via puncture wounds, needle injection, castrations, lacerations, and foot abscesses.  The vaccination is safe, effective, and very inexpensive.  Yearly vaccination is recommended.  If the horse is injured more than 6 months from the last vaccination, a booster is recommended.

Another vaccination that should be considered essential for any horse is West Nile Virus.  We have had at least two cases in the State of Washington and will almost certainly have more as we get into mosquito season.  The vaccination now has full FDA approval but will still only be available through veterinary clinics at this time.  Horses should get vaccinated annually in the spring before the mosquito season hits.  On a side note, last year California had 552 cases of West Nile Disease.  Of those, 231 died or were euthanized.  At least 239 were unvaccinated and 86 were improperly vaccinated.  If traveling to California or the southeast U.S. it is probably wise to vaccinate every six months. 

Highly Recommended:

Influenza (Flu) vaccination is highly recommended especially for performance horses that will be traveling to and from shows and for horses living in large stables.   New information is showing that Intervet’s Flu-Avert IN and Boehringer Ingelheim’s Calvenza vaccine may provide better protection against Influenza than other vaccines when used according to labeled directions.   Also, like in humans, influenza immunity does not last long.  With that in mind, performance horses and young horses should get at least two influenza boosters per year.   For horses on the road year round, quarterly vaccination may be advised.  Backyard or pleasure horses that do not come in contact with other horses will probably be fine with yearly influenza vaccination in the spring.  If the horse must compete or travel shortly after vaccination, it is best to use the Intranasal Flu-Avert vaccine because it will give a quicker and stronger early response.  Calvenza can also be given intra-nasally if the horse has had the initial intramuscular series.

Vaccination for Eastern and Western Encephalitis is also recommended for pleasure or performance horses traveling south or east of the Cascade Mountains.   We don’t see EEE or WEE here in Northwest WA, but can occur in warmer climates especially in the southeast and even California where mosquitoes are a problem.  Annual vaccination in the spring before the mosquito season is the typical protocol.

Vaccination for Rhinopneumonitis has been the topic of considerable debate over the past few years.  “Rhino” is a herpes virus that can cause respiratory disease, neurologic disease, and most importantly abortion in mares.  Many horses harbor the virus in their system without any ill effects.  Currently there are no vaccinations available that do a very good job of inducing a protective immunity that lasts more than a couple of months.   The vaccine may be beneficial for high risk horses traveling a lot.  They would need to be vaccinated 3-4 times year.  We still recommend vaccination of pleasure horses because outbreaks do occur, and even if the efficacy is questionable, it is a relatively safe vaccine and may offer some protection.  The definite exception is pregnant mares.   Since “Rhino” is a common cause of abortion, we recommend vaccination before breeding and on the 5^th, 7^th, and 9^th month of pregnancy.  The Rhino vaccines for pregnant mares have a high level of virus and seem to offer good protection against abortion. 

Optional: 

Vaccines that are of variable value in our area would include Strangles, Rabies, Botulism, Equine Protozoal Myelitis, and Potomac Horse Fever.  Rabies is very uncommon in Washington but if you are traveling to the East for any length of time you may consider it.  Botulism is seen some in the Southwest and Kentucky but is usually a problem on an individual farm.  If traveling on the East Coast during the spring and summer months Potomac Horse Fever vaccination would be important.

Strangles vaccines have also been a topic of great debate.  The vaccines that we have only offer partial protection and in fact some may even make the horse quite sick.  A newer intranasal vaccine may help reduce infection or at least reduce the severity of disease without the risks of the intramuscular vaccines.    We don’t routinely recommend vaccination for Strangles unless you are going to a farm known to have problems or if there is an outbreak of disease.  Another concern would be for young stock or horses near auctions or animals that are exposed to new horses from auctions.

There is a vaccine for Equine Protozoal Myelitis (EPM), but it is still under conditional licensure and undergoing efficacy studies. 

Your local veterinarian would be the best source of information to determine your risk for these vaccinations.

Important Points:

Ø      If a horse has never had a vaccination to a particular disease or if the history is unknown, they must have a primary vaccination followed by a booster in 3-6 weeks followed by an annual or semi-annual booster.

Ø      Pregnant mares should get vaccinated on the 5^th, 7^th, and 9^th month of pregnancy for Rhino, as well as a vaccination for Flu, Rhino, Tetanus, and West Nile Disease 4 weeks before foaling to ensure good protection to the foal from the colostrum.

Ø      Avoid administering vaccines during stress times (i.e., bad weather, weaning, travel, etc.)