Key points at a glance:
- Tetanus is considered an indispensable core vaccination and is often life-saving.
- Antibody titer testing is the safest way to assess whether a tetanus booster is truly necessary and helps prevent unnecessary vaccinations.
- Influenza and herpes vaccinations should be critically evaluated and administered only to competition horses, broodmares, or in herds with a high infection risk.
- Influenza and herpes vaccinations carry a higher risk of adverse reactions, which is why indications should be set very strictly.
- West Nile virus (WNV) is widespread but only rarely fatal; vaccination decisions should be based on the individual horse’s risk.
- As a general rule: responsible preventive care means vaccinating as much as necessary—but as little as possible.
Preventive health care is the foundation of good horse management. When it comes to vaccinations, however, many horse owners find themselves in a gray area between routine and necessity. The blanket recommendation “vaccination is always good” is outdated. Instead, every vaccine should be subjected to a strict risk–benefit analysis. Vaccinations are medical interventions and can cause side effects—so-called vaccine reactions or vaccine injuries.
Tetanus: indispensable basic protection and the titer alternative
Tetanus is an infectious disease with an extremely high mortality rate in horses—close to 100 percent. The tetanus vaccination is therefore the only vaccination considered essential for every horse, regardless of age, management, or use. In this case, the benefits far outweigh the risks.
But does tetanus really need to be boosted every year?
In many cases, the answer is no. Protection against tetanus often lasts significantly longer than the commonly recommended three years. To avoid unnecessary vaccinations, antibody titer testing is available. A blood sample is analyzed using a rapid test to determine how many tetanus antibodies are still circulating in the bloodstream. If the titer is sufficiently high, the booster can safely be postponed. This protects the horse’s immune system and avoids unnecessary strain.
Influenza and herpes: risk versus regulations
Vaccination against equine influenza and equine herpesvirus (EHV) is often the subject of heated debate among horse owners and veterinarians. Both viruses are highly contagious and widespread, yet the vaccines are known not only for failing to provide sterile immunity, but also for causing more frequent and sometimes pronounced vaccine reactions.
Equine influenza
Influenza vaccination is mandatory for all competition horses participating in national or international events. In large herds or boarding stables with frequent horse traffic, it may also be required as part of herd-level preventive management.
The benefit lies in reducing disease duration and viral shedding. The risk involves potential vaccine reactions, ranging from mild swelling to more severe systemic responses. As a responsible horse owner, you should ask yourself: is my horse a leisure companion with minimal contact with unfamiliar horses? If so, the necessity of annual vaccination should be critically questioned. If, however, the horse travels frequently, vaccination serves to protect the entire stable population.
Equine herpesvirus (EHV)
EHV can cause respiratory disease, neurological symptoms, and—most feared of all—abortions in pregnant mares.
Vaccination is primarily required for broodmares (for abortion prevention) and in breeding operations or facilities with a known EHV risk, often mandated by the stable operator. For the average leisure gelding, the benefit relative to the possible vaccine reactions—particularly the risk of neurological complications, which are rare but serious—is usually too low to justify routine vaccination. Prevention in this case focuses on minimizing risk through isolation of infected horses. If an outbreak occurs, strict quarantine measures for the entire stable and especially the affected horse are generally sufficient to contain it quickly.
West Nile virus (WNV): a regional risk-based decision
West Nile virus is transmitted by mosquitoes and can be endemic. Horses are considered dead-end hosts: they can become ill but do not transmit the virus to other horses. Most infections are asymptomatic; only rarely do neurological symptoms occur, and in severe cases, death.
Here, the risk of vaccination must be weighed against the risk of a potentially fatal disease. Because WNV prevalence varies regionally, this decision is highly individual. Preventive care often also includes consistent mosquito control during the season. If you are unsure, discuss with your veterinarian or therapist whether your location and your horse’s management actually warrant vaccination.
Checklist: the path to individualized vaccination prevention
To protect your horse responsibly and optimally, consider the following steps:
- Review the vaccination record: what has been vaccinated in the past?
- Check tetanus titers: ask your veterinarian about antibody testing to assess the duration of basic protection.
- Assess management conditions: how high is the infection risk? (Leisure horse, sport horse, pasture board, competition stable, breeding operation?)
- Critically evaluate indications: vaccinations should only be administered if they are legally required or essential for herd-level prevention.
- Documentation: every vaccination is recorded in the equine passport. Observe your horse closely in the days following vaccination for any adverse reactions and document them to reassess risks with your veterinarian before the next scheduled vaccination.
The best preventive care for your horse is an individualized, well-informed decision. By critically questioning vaccinations and using alternatives such as antibody titer testing, you protect your horse’s long-term health and ensure that the immune system is not burdened unnecessarily.
