Study Shows Hendra Vaccine Boosts Horses' Immunity

New data from Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO) shows that horses exposed to a lethal dose of hendra virus six months following vaccination did not develop disease.

Commenting on the CSIRO study, the Australian Veterinary Association (AVA) confirms that horses exposed to lethal doses of the virus were protected for six months after they completed a full course of the Equivac HeV vaccine.

According to Ben Gardiner, BVSc, CMAVA, president of the AVA, the new data should further increase horse owner confidence in the vaccine and support veterinarians’ efforts to vaccinate horses under their care.

“The outcome of this study is an important step in the ongoing fight against the hendra virus,” said Gardiner. “Vets and horse owners alike can now have even greater assurance that the most effective tool against this lethal virus has significant immunity.”

CSIRO’s Australian Animal Health Laboratory played a critical role in the development of Equivac HeV and continued efforts to minimize hendra virus spread, including the study conducted to confirm six months’ immunity.

“Supporting the equine community has always been our main priority and this recent data is providing further confidence to owners, vets and those that interact with horses,” said Deborah Middleton, BVSc (Hons), MVSc, PhD, Dipl. VCS, a veterinary pathologist at the CSIRO. “While any vaccine may not be a silver bullet, this new information consolidates the position of Equivac HeV as a significant weapon in the arsenal against hendra.”

Although the vaccine represents a significant advancement in the way that veterinarians manage hendra risk, there is work under way to further understand the vaccine’s full potential.

“While we are very pleased with the outcome of this study, we believe that protection will likely persist for even longer, and studies are continuing to confirm this and other key indicators of the vaccine’s performance,” said Middleton.

Since the vaccine’s introduction in November 2012, the AVA has been working with its members to educate and encourage horse owners to protect their horses, themselves, and their community through vaccination against the hendra virus.

“These research results further support our recommendation that all horses in Australia should be vaccinated to reduce fatal outcomes that result from hendra virus infection,” said Gardiner.

Hendra virus has been known to yield numerous clinical signs in horses including respiratory distress, frothy nasal discharge, elevated body temperature (above 40°C, or 104°F), and elevated heart rate; however, authorities caution that hendra infection does not have specific signs. The disease is zoonotic, meaning it can be transmitted from horses to humans, and as proved deadly for several humans exposed to sick horses in the past.

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