New equine flu vaccine could take years to develop

An equine flu vaccine protecting horses against a new strain of the disease could take years to develop, according to the Animal Health Trust.

British racing was brought to an abrupt halt on Thursday after it was discovered that three horses from Donald McCain's yard had tested positive for equine flu – despite being vaccinated.

Dr Richard Newton, director of epidemiology and disease surveillance at the Animal Health Trust, said it appeared a slight mutation in the virus enabled it to affect animals who have been vaccinated.

"We don't think this is a brand new strain of the virus," said Dr Newton. "But we suspect it has undergone a slight change that has allowed it to effectively infect animals who have been vaccinated.

"Developing new vaccines for horses is frustratingly slow compared to humans, where vaccines are updated very quickly and go out almost fresh each year. Unfortunately we don't have that speed, and we're looking at a number of years before a vaccine can be updated.

"The crucial thing [now] is how effective the [current] vaccine remains, particularly in animals where we're boosting them in light of this new threat."

Dr Newton advised that following the outbreak, horses who have not received their annual booster within the last six months should be given it immediately.

"Hopefully we can boost those animals sufficiently and they'll have enough immunity to help fight this off.

"In due course there'll be a review of what's gone on – why the vaccines are no longer working – but the viruses [used to develop] this vaccine are 15 years old, so it won't be a complete surprise if we've reached the point where we need to update them."

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