Spring Shots: A guide to Equine Vaccines and Propper Protection

Written by 4th year veterinary student, Kristina Fisher

As the days grow longer and the weather warms up, horse owners are eager to get back to riding, showing, and trail adventures. But before you saddle up for spring, there’s one essential item to check off your horse’s health checklist—vaccinations. Spring is the perfect time to ensure your horse is protected against serious diseases, some of which are spread by insects that become more active as temperatures rise. The American Association of Equine Practitioners (AAEP) divides vaccines into two categories: core vaccines (recommended for all horses) and risk-based vaccines (recommended based on a horse’s lifestyle, location, and level of exposure). In this guide, we’ll cover the core vaccines every horse needs, risk-based vaccines for specific situations, and why spring is the ideal time to schedule your horse’s shots.

Core Vaccines: Every Horse, Every Year

Core vaccines protect against diseases that are widespread, highly fatal, or pose a risk to public health. Every horse should receive the following vaccines annually:

1. Tetanus:

•Why It’s Important: Tetanus is caused by a toxin-producing bacterium found in soil, manure, and rusty metal objects. It enters the body through wounds, surgical sites, or punctures, leading to painful muscle stiffness and potentially fatal paralysis.

•When to Vaccinate: Tetanus is technically labeled for annual vaccination, however, it is bundled with the EEE/WEE vaccine resulting in at least twice yearly boosters.

2. Eastern & Western Equine Encephalomyelitis (EEE/WEE):

•Why It’s Important: These viral diseases, also known as “sleeping sickness,” attack the nervous system and have high fatality rates (almost 100%). They are spread by mosquitoes, making spring vaccination crucial before mosquito season begins.

•When to Vaccinate: Every 6 months

3. West Nile Virus (WNV):

•Why It’s Important: Another mosquito-borne disease, WNV causes neurological symptoms such as muscle tremors, weakness, and incoordination. It can be fatal in up to 30% of cases.

•When to Vaccinate: Annually in early spring, with possible boosters in high-risk regions.

4. Rabies:

•Why It’s Important: Rabies is a deadly viral disease that affects the nervous system and can be transmitted to humans. It is transmitted through saliva.

•When to Vaccinate: Annually, as a single dose.

Risk-Based Vaccines: Protecting Horses Based on Lifestyle & Location

In addition to core vaccines, some horses benefit from additional vaccinations based on their risk factors. Your veterinarian can help determine which of these are necessary for your horse:

1. Influenza & Rhinopneumonitis (Equine Herpesvirus- EHV-1 & EHV-4):

•Who Needs It? Horses that travel, compete, or come into contact with new horses frequently. Additionally, it is recommended for horses kept in boarding facilities

•Why It’s Important: These contagious respiratory viruses cause fever, coughing, nasal discharge, and, in severe cases, neurological issues.

•When to Vaccinate: Every 6 months for at-risk horses.

2. Strangles (Streptococcus equi):

•Who Needs It? Horses in boarding barns or show circuits when where the risk of exposure is high.

•Why It’s Important: This highly contagious bacterial infection causes swollen lymph nodes, abscesses, and respiratory distress.

•When to Vaccinate: Annually for at-risk horses. An intranasal vaccine is available.

Why Spring Is the Best Time to Vaccinate

Spring vaccinations ensure your horse is protected before peak disease exposure. Mosquito-borne illnesses like WNV and EEE/WEE become a greater risk as temperatures rise, while horses heading to shows, clinics, or trail rides are more likely to encounter contagious respiratory diseases.

Final Tips for a Smooth Vaccination Appointment:

•Always make sure that your horse has had their initial booster series. If the vaccine history is unknown, we recommend that the booster be repeated. The vaccine WILL NOT be protective without an initial booster series.

•Monitor for Reactions: Mild swelling or soreness at the injection site is normal, but contact your vet if your horse experiences fever, lethargy, or severe swelling.

•Keep Records: Maintain a vaccination log to track your horse’s health history and meet boarding, travel, or competition requirements.

Schedule your horse’s spring vaccines today—because prevention is always better than treatment!