This article first appeared in the January/February 2016 issue (27) of Equestrian Life. To see what is in our latest issue, please click here.

The Hendra vaccine has been met with mixed repsonses.

HENDRA VACCINE SHOULDN'T BE COMPULSORY, PARLIAMENTARY COMMITTEE FINDS

The following letter was written in response to Ryan’s Rave, EQ Life issue 27.

THE HENDRA VIRUS is a deadly zoonotic disease that has killed four people and nearly 100 horses.

Its incidence is increasing. In the past five years, there have been more than 40 spillover events in Queensland and New South Wales. In every case at least one horse dies. I have witnessed the devastating effects this virus has on those involved: the fear of exposure, an agonising 30-day wait to be cleared, and the regret expressed by owners that they didn’t protect themselves, their families, friends and horses with vaccination.

Hendra virus is rare, but its symptoms in horses are non-specific and easily mistaken for common conditions. Some horses appear to have colic, others may simply go off their feed or appear lethargic. There have even been infected horses without any noticeable symptoms. Veterinarians face the difficulty of diagnosis, suiting up and suiting down in full PPE in heat and humidity, unable to leave behind medications and warning owners to stay away from a horse that probably will not have Hendra but where the safety-first approach must be paramount. Communication from Queensland government authorities to veterinarians recently has been to the effect that “if Hendra cannot be ruled out, then it must be ruled in.”

Many horse owners would not suspect Hendra when a horse shows symptoms
like colic, or going off their feed. They would tend to their loved horse, not realising they were exposing themselves to a deadly virus.

By the time a veterinarian has warned them that the horse could have Hendra virus, it could be too late. In 2014, six horse owners had exposure to Hendra virus considered so extreme they were offered an experimental treatment in a Brisbane hospital. The treatment is administered intravenously, with adrenalin
at the ready in case of anaphylaxis.

This year, workplace health and safety prosecutions were commenced against three veterinarians who were accused of not maintaining a safe workplace. Horses they treated turned out to have Hendra virus. Veterinarians face a real threat to their health and now a legal threat to their livelihoods when diagnosing
and treating unvaccinated horses. Veterinarians, of course, are not the only people with workplace health and safety obligations, which is why sporting bodies, event organisers and others often conclude that vaccination is an obvious, sensible precaution.

The Hendra vaccine became available in late 2012 following ground-breaking work by the CSIRO, Zoetis and international research partners. As part of the original permit, veterinarians were required to report every suspected adverse event, and every dose has been documented and administered by a veterinarian. Zoetis assesses each report received and classifies it as to the likelihood of the symptoms reported being attributable to vaccine administration. All reports are conveyed to the Australian Pesticides and Veterinary Medicines Authority which makes an independent assessment.

I have personally examined every adverse event report concerning the Hendra vaccine received by Zoetis. The majority are typical of the experiences many people have with human vaccines: temporary soreness or swelling around the injection site, sometimes a temperature, or being off colour for a day or so. Phenylbutazone (bute) is commonly recommended by veterinarians for the treatment of horses experiencing an adverse reaction or as a preventative for horses that have previously experienced a reaction, but is not recommended for horses that have not experienced a reaction.

Australia’s very thorough regulator had the benefit of seeing the adverse report data generated from 350,000 doses administered as part of the registration application. The APVMA was satisfied as to the safety of the vaccine and proceeded to register it. The vaccine is demonstrably safe and effective. It is
widely used as a health and safety tool by owners, breeders and the mounted units of state police forces. For these reasons, it is disappointing to read a single critic’s view of the vaccine in your November/December edition. Those views are not backed by evidence and are contrary to the assessment of Australia’s peak regulatory, scientific and veterinary bodies. Government agencies routinely describe the Hendra vaccine as the single most effective way of reducing the risk of infection in horses, and therefore people. This view is supported by extensive studies. Since its release there has not been a single vaccinated horse contract the Hendra virus, while there have been 15 spillover events involving unvaccinated horses.

Everyone involved with horses in Australia is fortunate to have a safe, high quality vaccine to help protect against a deadly virus. The Hendra vaccine deserves wider use to protect horses, veterinarians, owners and their families. Owners should speak with their veterinarian in order to make a sensible and informed decision as to whether to vaccinate their horses.

Dr Richard L’Estrange, BVSc, MANZCVS,
Veterinary Operations Manager,
Zoetis Australia.

 

This article first appeared in the January/February 2016 issue (27) of Equestrian Life. To see what is in our latest issue, please click here.

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