Vaccination against influenza in horses
Influenza, also known as equine flu, is a highly contagious respiratory infection caused by the equine influenza virus.
A horse with influenza may suddenly develop a high temperature, cough frequently, have nasal discharge and be noticeably less energetic. The infection spreads easily through the air and through contact between horses. The virus can spread particularly quickly at stables, during transport and at competitions.
Vaccination helps reduce the severity of the disease and may limit the spread of the virus. However, vaccinated horses can still become infected.
Influenza vaccination schedule
A standard vaccination schedule begins with a primary vaccination course. The horse receives two vaccinations several weeks apart, followed by a third vaccination after approximately five to six months. The vaccination is then generally repeated annually.
A shorter interval may be advisable or compulsory for horses that have frequent contact with other horses or regularly attend competitions.
The exact schedule depends on the vaccine used and any competition rules. Ask your vet to draw up a suitable schedule.
Vaccination against tetanus in horses
Tetanus, also known as lockjaw, is caused by a toxin produced by the bacterium Clostridium tetani. The bacterium is found in the environment, including in soil and manure, and can enter the body through a wound.
Horses are particularly susceptible to tetanus. The toxin affects the nervous system and causes severe muscle stiffness and muscle spasms. A horse may have difficulty chewing, swallowing and moving. In severe cases, the respiratory muscles may also be affected.
Tetanus is a life-threatening condition. Vaccination against tetanus is therefore strongly recommended for virtually all horses, even if they do not compete or have little contact with other horses.
Tetanus vaccination schedule
The primary vaccination course generally consists of two vaccinations approximately four to six weeks apart, followed by an additional vaccination according to the manufacturer’s schedule.
The tetanus vaccination is then usually repeated every two to three years, depending on the vaccine used.
Tetanus is often combined with the influenza vaccination. As the protection schedule can vary between vaccines, it is important that the vet follows the correct intervals.
Does your horse have a deep or contaminated wound, and is its vaccination status unknown or incomplete? Contact your vet immediately. Additional protection with tetanus antitoxin may sometimes be required.
Vaccination against equine rhinopneumonitis
Equine rhinopneumonitis is caused by equine herpesvirus, mainly EHV-1 and EHV-4. These viruses are common in horses and can cause a range of symptoms.
The most common form causes respiratory symptoms such as a high temperature, coughing and nasal discharge. EHV-1 can also cause abortion in pregnant mares and, in some cases, severe neurological symptoms such as coordination problems and paralysis.
A particular characteristic of herpesviruses is that they can remain in the body after an infection and become active again later.
Equine rhinopneumonitis vaccination schedule
Under a standard vaccination schedule against EHV-1 and EHV-4, the horse receives two primary vaccinations approximately four to six weeks apart. The vaccination is then generally repeated every six months.
Additional vaccination advice applies to pregnant mares. To reduce the risk of abortion caused by EHV-1, vaccines authorised for this purpose are often administered during the fifth, seventh and ninth months of pregnancy.
Vaccination can reduce respiratory symptoms and viral shedding, but it does not completely prevent infection. Vaccination also does not provide reliable protection against the neurological form of equine rhinopneumonitis.
Good hygiene, limiting contact with sick horses and careful stable management therefore remain important.
Would you like to learn more about this disease? Read our detailed blog about rhinovirus in horses.
Vaccination against West Nile virus in horses
West Nile virus is mainly transmitted by mosquitoes. Birds play an important role in spreading the virus. Horses can become infected when they are bitten by an infected mosquito.
Many infected horses develop no symptoms or only mild symptoms. However, in a small proportion of horses, the virus can affect the nervous system. This can lead to muscle tremors, uncoordinated movement, weakness and sometimes paralysis.
There is no specific antiviral treatment for West Nile virus in horses. Preventing infection is therefore important.
West Nile virus vaccination schedule
The primary vaccination course against West Nile virus generally consists of two vaccinations approximately three to six weeks apart, depending on the vaccine used.
The vaccination is then repeated annually. It is advisable to complete the primary vaccination course well before the mosquito season so that the horse has time to build up protection.
Whether vaccination is recommended for your horse depends on factors such as the risk of infection in the region and any travel to areas where the virus is present.
In addition to vaccination, it is important to prevent mosquito bites as much as possible. For example, limit standing water around the stable, use suitable insect repellents and protect horses during periods when there are large numbers of mosquitoes.
Read more about transmission, symptoms and prevention in our blog about West Nile virus in horses.
Horse vaccination schedule: how often should you vaccinate?
The following schedule can be used as a general guideline for a healthy horse.
| Disease |
Primary vaccination course |
Repeat vaccination |
| Influenza |
Two vaccinations several weeks apart, followed by a third vaccination after approximately five to six months. |
Usually annually. |
| Tetanus |
Two vaccinations approximately four to six weeks apart, followed by an additional vaccination according to the package leaflet. |
Usually every two to three years. |
| Equine rhinopneumonitis |
Two vaccinations approximately four to six weeks apart. |
Usually every six months. |
| West Nile virus |
Two vaccinations approximately three to six weeks apart. |
Annually. |
This is a general overview. The exact vaccination schedule may vary depending on the vaccine, age and circumstances. Specific rules also apply to competition horses.
Which vaccinations are compulsory for competition horses?
If you take part in official competitions organised by the Royal Dutch Equestrian Federation, the Koninklijke Nederlandse Hippische Sportfederatie (KNHS), with your horse, a valid influenza vaccination is compulsory.
The primary vaccination course your horse must have received depends on its year of birth and when the primary vaccination course was started.
Horses born before 1 January 2022
For horses born before 1 January 2022 whose primary vaccination course was completed in accordance with the rules that applied at the time, the primary vaccination course consists of two vaccinations.
There must be at least 21 days and no more than 92 days between the first and second vaccinations.
The horse may not compete during the period between these two vaccinations.
Horses born in 2022 or later
For horses born in 2022 or later whose primary vaccination course was started under the rules that applied before 1 April 2024, the primary vaccination course consists of three vaccinations.
The second vaccination must be administered at least 21 days and no more than 92 days after the first vaccination. The third vaccination must be administered at least 120 days and no more than seven months after the second vaccination.
The horse may not compete between the first and second vaccinations. Competition is permitted between the second and third vaccinations, provided the most recent vaccination was administered at least seven days before the competition.
New primary vaccination courses from 1 April 2024
For all horses whose primary vaccination course is started on or after 1 April 2024, a schedule of three vaccinations applies, regardless of the year of birth.
The second vaccination must be administered at least 21 days and no more than 60 days after the first vaccination.
The third vaccination, also known as the first booster, must be administered at least 120 days and no more than six months plus 21 days after the second vaccination.
The horse may not compete between the first and second vaccinations. It may compete between the second and third vaccinations, provided the most recent vaccination was administered at least seven days before the competition.
Annual booster vaccination
After a valid primary vaccination course, the influenza vaccination must be repeated annually. This means that the next vaccination must be administered no later than the same calendar date in the following year.
A horse may also not compete within seven days after a vaccination.
Horses with an older primary vaccination course that was completed correctly do not automatically require a new primary course of three vaccinations. The existing vaccination history remains valid as long as it complies with the applicable rules and the booster vaccinations have been administered correctly.
Overview of the vaccination schedule for KNHS competition horses
| Situation |
Primary influenza vaccination course |
Competition participation |
| Born before 1 January 2022, with an older valid primary vaccination course |
Two vaccinations at least 21 days and no more than 92 days apart. |
Not permitted between the first and second vaccinations. |
| Born in 2022 or later, with the primary vaccination course started before 1 April 2024 |
Three vaccinations. Second vaccination after 21 to 92 days. Third vaccination at least 120 days and no more than 7 months after the second. |
Not permitted between the first and second vaccinations. |
| Primary vaccination course started on or after 1 April 2024, regardless of year of birth |
Three vaccinations. Second vaccination after 21 to 60 days. Third vaccination at least 120 days and no more than 6 months plus 21 days after the second. |
Not permitted between the first and second vaccinations. |
| After a valid primary vaccination course |
Annual booster vaccination, no later than the same calendar date in the following year. |
Not permitted within 7 days after a vaccination. |
For all KNHS competition horses, a vaccination must have been administered at least seven days before the competition. Source: KNHS.
Recording vaccinations in the horse passport
All influenza vaccinations must be recorded correctly on the ‘Influenza vaccinations’ page of the horse passport. Other vaccinations, such as those against tetanus, equine rhinopneumonitis and West Nile virus, are recorded on the ‘Other vaccinations’ page.
A vaccination record is only valid if it includes the date, the vaccine batch number, and the vet’s signature and practice stamp. Any corrections must also be signed and stamped by the vet.
If previous vaccinations were recorded in a separate vaccination booklet, the vet must confirm the vaccination history in the horse passport in the prescribed manner. In an FEI passport, this is done using the English declaration: The vaccination history of this horse/pony is correct. Last vaccination on: [date]. In other passports, this declaration may also be included in Dutch.
The declaration must be signed and stamped by the vet.
Influenza at international FEI competitions
Additional requirements apply to international competitions held under the Fédération Équestre Internationale (FEI).
Following a valid primary vaccination course, the influenza vaccination must be repeated annually. To take part in an FEI event, the most recent vaccination must also have been administered within six months plus 21 days before the event.
At FEI competitions, the horse may also not arrive at the event within seven days after vaccination.
Always check the current FEI rules when taking part in international competitions. These may differ from the national KNHS regulations.
Are vaccinations against tetanus, equine rhinopneumonitis and West Nile virus also compulsory?
For regular KNHS competitions, influenza is the vaccination for which specific general participation requirements apply.
Vaccinations against tetanus, equine rhinopneumonitis and West Nile virus are not routinely compulsory for every KNHS competition. However, vaccination may be strongly recommended for health reasons.
Additional requirements may apply at competitions abroad, international events or specific venues. Always check the requirements of the organisation and the country you are travelling to in advance.
For the current rules, also consult the KNHS information about vaccinations for competition horses.
Vaccination is part of good healthcare
Vaccination is important, but it does not offer complete protection against every disease. Good care and a healthy living environment therefore remain essential.
Ensure adequate ventilation in the stable, limit dust and moisture, and keep feeding and drinking facilities clean. If a horse has a high temperature, is coughing or has nasal discharge, it is advisable to limit contact with other horses and consult your vet.
Parasite control is also part of preventive healthcare. Vaccinations do not protect against worm infections. It is therefore advisable to have regular faecal examinations carried out and, on that basis, determine a suitable worming policy with your vet. Read more in our blog about worms in horses and worming schedules.
When is the best time to have your horse vaccinated?
Your horse should preferably be vaccinated when it is healthy. If your horse has a high temperature or other signs of illness, ask your vet whether the vaccination should be postponed.
For influenza and equine rhinopneumonitis, it is advisable to consider times when your horse will have a lot of contact with other horses. Examples include competitions, training sessions, moving yards and transport.
For West Nile virus, it is beneficial to complete the vaccination course before the mosquito season.
Always have vaccinations recorded correctly in the horse passport. This is particularly important if you want to take part in competitions with your horse.
Conclusion: which vaccinations does your horse need?
Influenza and tetanus form the basis of a good vaccination programme for many horses. Depending on housing, contact with other horses, breeding activities and the regional risk of infection, vaccinations against equine rhinopneumonitis and West Nile virus may also be advisable.
Specific influenza vaccination requirements also apply to competition horses. It is particularly important to plan vaccinations carefully for international competitions.
Discuss which vaccinations your horse needs and the appropriate schedule with your vet. This helps protect not only your own horse but also reduces the risk of infectious diseases spreading within the horse population.
