The sudden collapse of a pony after a Hendra vaccination has sparked a social media frenzy with hundreds of horse owners reporting varied adverse reactions to the Hendra vaccine. Amelia Starkey (pictured) from Woombye was on her way to competing at a high level with her beloved horse Koda, but sadly he has suffered a series of adverse reactions since having the Hendra vaccine and they are no longer able to compete.Amelia's mother Vanessa Starkey said Koda was the 'perfect' pony, "But about a month after we made the conscious decision to vaccinate Koda, he started misbehaving and now suffers serious neurological problems such as anxiety, anger and unpredictable behaviours," Vanessa explained. "We were suppose to have another booster but because of problems with his immune system I chose for him not to have another shot because he was not well and having treatment for an infection in his leg.""His symptoms have not been confirmed by the vets as most reactions are classed as possible or probable but these reactions are being widely experienced throughout Qld with vaccinated horses," Vanessa said."We thought we were doing the right thing for him, it is just tragic to see him suffering every day. It has cost thousands to treat him and there is no guarantee he will ever return to full form, all we want is the vaccine to be made safe for horses and full access to veterinary care  for horses that are not vaccinated."There are many Hendra vaccinated horses that have not reacted adversely, but these owners are also expressing increasing concerns on social media sites. In this edition the Gazette talks to a Sunshine Coast Vet who is calling for further study on the Hendra vaccine.