Equine Vaccination Recommendations

Our doctors’ recommendations about what to vaccinate against and when to do it.

What do the vaccination abbreviations mean?

EWT: Eastern and Western Equine Encephalitis, Tetanus
VEE: Venezuelan Equine Encephalitis (not considered a threat in our area)
WNV: West Nile Virus
Flu: Equine Influenza
Rhino: Rhinopneumonitis (Equine Herpes Virus 1 and 4)
Strangles: Strangles/Streptococcus equi (no longer vaccinated for routinely)

Adult Horses

Spring (March-May): EWT*/WNV (and Flu/Rhino if high risk)
Fall (September-October): Flu/Rhino boosters if high risk

* Tetanus should be boostered if a horse is injured, has surgery or develops an abscess and has not received the vaccine within the last 9 months.

A horse may be at high risk for Flu/Rhino if it frequents shows, organized trail rides, rodeos, etc. Any situation where it is exposed to many strange horses.


Pregnant mares should be current on all vaccines prior to breeding.

5th, 7th, 9th month: Rhino
30 days prior to due date: EWT/WNV and deworming


Foals require an initial vaccination followed by 2 boosters to develop full immunity. Vaccination recommendations vary depending on the vaccination status of the mother and when maternal antibodies decline.

Foals from vaccinated mares

6, 8, 10 months of age: EWT/WNV

Foals from unvaccinated mares

at birth: Tetanus antitoxin
3, 5, 7 months of age: EWT/WNV

The information on this page is also available as a printable PDF. You can download it here:

© 2014 Animal Hospital of Pasco, P.S. [admin]