Pilot Field Vaccine Trial for Equine Grass Sickness

The main purpose of the pilot field vaccine trial was to gather information about the feasibility of performing a larger vaccine trial on a national scale in Great Britain. The study was therefore designed to test the methods used in the vaccine trial rather than the vaccine itself.

The pilot study focussed specifically on:

  • identifying the best way of recruiting veterinary practices and horse / pony owners interested in taking part in an EGS vaccine trial.
  • identifying the most effective method for co-ordinating vaccination of all enrolled horses and ponies within a short time period.
  • informing the most effective methods for gathering information about the health and management of all enrolled horses and ponies at regular intervals throughout the trial.
  • measuring the immune response to vaccination with the Clostridium botulinum type C toxoid vaccine

The pilot study provided valuable information which has been used to inform the recruitment and monitoring phases for the full scale nationwide EGS vaccine trial. Co-ordination of treatment administrations was straightforward and participating owners and veterinary surgeons did not report any difficulties in undertaking the scheduled field visits.

No systemic adverse reactions were reported and the incidence of local injection site abnormalities was low. No interactions between the vaccine or placebo and any other treatments were reported throughout the study period.

Blood tests showed that horses and ponies in the vaccinated group had significantly greater increase in antibody levels following the primary treatment course compared to those in the placebo treatment group, indicating immune response to primary vaccination.

The full text of the study can be read here:

Pilot Study