Equine Grass Sickness vaccine trial FAQ
What type of vaccine is being used in the nationwide EGS vaccine trial?
The vaccine used in this EGS field vaccine trial is a toxoid vaccine, containing inactivated Clostridium botulinum type C toxins. This vaccine is very similar to the tetanus toxoid vaccine commonly used to prevent tetanus in horses and ponies.
Can the vaccine cause EGS?
No – because the vaccine contains inactivated Clostridium botulinum type C toxins, it would not be possible for the vaccine to cause EGS.
How can you tell if the vaccine prevents EGS?
EGS cannot be reproduced experimentally; therefore a field vaccine trial is the only way to determine whether vaccination against Clostridium botulinum type C prevents EGS. Half of the horses and ponies on the trial will be vaccinated with the Clostridium botulinum type C toxoid vaccine; the other half of the horses and ponies will receive an inactive placebo injection. Comparing the number of EGS cases occurring within the vaccinated group to with the number of EGS cases occurring within the placebo-treated group will show whether or not vaccination significantly reduces the risk of EGS.
What is a placebo injection?
A placebo is an inactive substance containing no medication, used as a control in tests to determine the effectiveness of a medicinal drug/vaccine. In the EGS vaccine trial, the placebo injection will have the same formulation as the vaccine except that it will not contain the active component (the inactivated Clostridium botulinum type C toxins).
Who would be administering vaccine or placebo injections during the vaccine trial?
Horses and ponies enrolled in the vaccine trial would remain under the care of the veterinary practice with which they are registered throughout the trial, and we hope that your usual veterinary practice will be able to carry out each visit. Specifically trained EGS vaccine trial veterinary surgeons would also be available to perform health checks and administer vaccines or placebo injections for your horses/ponies if, for any reason, your usual veterinary practice were unable to.
How many veterinary visits are involved in the vaccine trial?
The EGS vaccine trial involves a minimum of 4 veterinary visits during the first year, and a further 2 veterinary visits in the second year. All veterinary visits included in the vaccine trial would be conducted during the normal working hours of the veterinary practice with which you are registered.
Would my horse or pony receive the vaccine or the placebo?
On each premises participating in the EGS vaccine trial, half of the horses and ponies will receive the vaccine and the other half will receive the placebo. Which treatment your horse or pony would receive will be selected at random at the start of the vaccine trial using computer-generated random numbers. To ensure the scientific validity of the EGS vaccine trial, neither you, nor your veterinary surgeon, nor the researchers will be informed of the treatment group which your horse or pony has been selected to join.
When will I find out whether my horse or pony received the vaccine or the placebo?
To ensure that the findings of the EGS vaccine trial are not influenced in any way by the expectations of people taking part, you will be informed of which treatment group your horse or pony was in once the final analysis of results has been performed at the end of the vaccine trial.
Will any details of the vaccine trial treatments be recorded in horse or pony’s passport?
Yes – following administration of each vaccine or placebo injection, your veterinary surgeon will record the date and batch number of the injection in the “vaccinations other than equine influenza” section of your horse or pony’s passport. At this time point, neither you nor your veterinary surgeon will know whether your horse or pony has received the Clostridium botulinum type C toxoid vaccine or the placebo, therefore the Animal Test Certificate number will be recorded in the “name of vaccine” section.
Can my horse or pony have other vaccinations at the same time as vaccine trial treatments?
Wherever possible, administering one of the trial vaccine or placebo injections at the same time as a routine vaccination (including influenza and/or tetanus or Equine Herpes Virus (EHV 1,4)) should be avoided, as it is possible that giving both vaccinations together might alter your horse or pony’s immune response to one or both of the vaccines. Allowing a period of two weeks between vaccine trial treatment administration and administration of other vaccinations is recommended (i.e. other vaccinations should be given more than two weeks before or more than two weeks after any trial treatment injection). Where it is not possible to avoid giving the trial treatment within two weeks of other vaccinations, we would ask that your veterinary surgeon administers the other vaccine in a different area (e.g. in the hindquarters or chest, rather than the neck).
My horse or pony has had EGS in the past – can I still take part?
No, unfortunately not. As we do not know how having EGS in the past may influence a horse or pony’s immune response to the vaccine, we will not be including any horses or ponies who have recovered from EGS in the vaccine trial.
I don’t see my horse or pony every day – can I still take part?
Yes – provided you have someone you can nominate on your behalf to attend veterinary visits and to check your horse or pony every day for the first week following each injection.
My mare is in foal – can I enrol her in the vaccine trial?
No, unfortunately not. As the vaccine has not yet been tested in pregnant mares, we will not be including any mares in foal, or mares with foals at foot.
My horse or pony is needle shy – should I enrol them in the vaccine trial?
We would advise that you discussed this with your veterinary surgeon before deciding whether or not to take part. The EGS vaccine trial involves several injections and blood samples, and there is a possibility that if your horse or pony is already frightened of injections, they may find taking part in the trial stressful.
Why would I have to complete several questionnaires during the vaccine trial?
It is very important that we are able to gather detailed information about the management and health of all enrolled horses and ponies throughout the EGS vaccine trial. The most convenient way for us to collect this vital information is via questionnaires at regular intervals.
Will taking part in the trial affect my horse or pony’s insurance cover?
Possibly – in every case, you would have to inform your insurance company before enrolling your horse or pony on the EGS vaccine trial. Your insurance company would then inform you of any changes they might make to your existing insurance policy if your horse or pony was enrolled in the trial.
Can I exercise my horse or pony after injections?
Yes – no specific exercise restrictions post-injection with either the vaccine or placebo would be required, and light exercise following injections is acceptable. However, extreme or high intensity exercise should be limited for a period of three days following each vaccine or placebo administration.
I compete my horse or pony – can I still take part?
Yes – however as competition rules of affiliated equestrian organisations can differ, we would advise that you seek clarification of competition rules with the appropriate affiliated equestrian organisation prior to deciding whether or not to participate. Enrolment in the vaccine trial would not affect a horse or pony’s eligibility to complete under competition rules of the Fédération Equestre Internationale (FEI), as the FEI have no specific requirements regarding vaccination except for equine influenza, details of which can be found at: http://www.fei.org/fei/horse-health-and-welfare/int-health-requirements/vaccinations
We will be able to provide you with a document detailing your horse or pony’s enrolment in the trial to accompany your passport for any required inspections.
I have a racehorse in training – can I still take part?
Yes – racehorses in training will be permitted to race during the vaccine trial, provided that vaccine or placebo injections are administered in compliance with the British Horseracing Authority Rules of Racing. As with other vaccinations, six clear days (starting from the day following injection) must elapse between vaccine administration and race day (as per Rule (B) Schedule 3 Part 1, 10.2 http://rules.britishhorseracing.com/Orders-and-rules&staticID=126400&depth=3). We will be able to provide you with a document detailing your horse’s enrolment in the trial to accompany your passport for any required inspections.
- These requirements apply only to races conducted under the British Horseracing Authority Rules of Racing. If you intend to enter, or it is possible that you might enter, your horse into any overseas race during the vaccine trial, you are advised to seek clarification of racing rules with the appropriate racing authority prior to deciding whether or not to participate.
- If your horse is not in training at the time of enrolment but begins training at some point during the vaccine trial, they would be permitted to race, provided that vaccine or placebo injections are administered in compliance with the British Horseracing Authority Rules of Racing as outlined above.
Are there any risks involved in participating in the vaccine trial?
Local reactions at the site of injection, such as slight swelling, heat or pain, can sometimes occur following intramuscular injections. In previous safety and pilot studies, both the vaccine and placebo have been shown to be safe, with a very small number of horses and ponies showing minor reactions at the site of injection, which did not require any form of treatment. As with any injection, there is always a small risk of injury to people handling the horse or pony and the veterinary surgeon at the time of injection.
What happens if my horse or pony develops signs of EGS during the vaccine trial?
At any point during the EGS field vaccine trial, if you are concerned that your horse or pony may be displaying clinical signs of EGS, you should contact your veterinary practice immediately. Your veterinary surgeon will then perform a clinical examination, any necessary further tests and administer any treatment required. In the case of acute or subacute EGS, a post mortem examination would be required to confirm the diagnosis of EGS. Where a diagnosis of chronic EGS is suspected, an additional veterinary examination by one of the specialist equine veterinary surgeons working on the vaccine trial would be required to obtain clinical confirmation of this diagnosis.
Is there any cost involved in participating in the vaccine trial?
Veterinary fees and costs directly related to the EGS vaccine trial, such as the vaccine and placebo injections, veterinary visits and blood test will be covered by the trial. You would however remain responsible for the costs of any routine veterinary and healthcare, and for the treatment of any condition or injury not directly related to the trial, such as on-going treatment for a long-term condition.
Season as a risk factor
The high risk season for EGS has now come to an end. However, cases can occur throughout the year and there is generally a small increase in incidence during the autumn months. To find out more about minimising the risk of this debilitating disease please click here
Horses and ponies from 39 different counties in
Scotland and England are currently enrolled in the
EGS vaccine trial.
EGS Vaccine Trial Facts and Figures: The most popular names amongst horses and ponies taking part in
the trial are ‘Jack’ and ‘Misty’, with close runners up
being 'Archie', 'Barney', 'Blue', ‘George’ and ‘Lady’.
The oldest horse participating in the trial is 29 years
while the youngest is 6 months old.
The average age of the horses and ponies enrolled on the trial is 8 years old.