Monday, March 18, 2013

Australia: Hendra Vaccine Hurdles



Credit WHO


# 7011


Hendra, a bat-borne virus found in Australia that occasionally infects horses and has killed at least four people over the past two decades, prompted the release of an equine vaccine last November (see Vaccine for killer Hendra virus launched).


Despite concerns over the virus, and urgings by the government, many horse owners have been slow to embrace this new vaccine.


A recent news report ('Lax' vets mean few Hendra vaccines) appearing in The Australian indicated that so far that fewer than 25,000 doses have been sold; far below the 120,000 anticipated by now, and low enough that there are now concerns the vaccine may not be a commercial success.

Recently the organizers of the show Royal Queensland Show in Brisbane (EKKA, an annual agricultural show) required all horses in attendance be inoculated, a move that some horse owners are resisting as the vaccine is relatively new, and full safety studies won’t be available until 2014 (cite).


Against this mixed backdrop, today we’ve some encouraging news from CSIRO (Commonwealth Scientific and Industrial Research Organisation) showing that at the six month mark, horses remain protected against the Hendra virus.  


This from ABC Rural news.


Hendra vaccine still working after six months

By Neroli Roocke

Monday, 18/03/2013

Researchers have confirmed that the Hendra virus vaccine gives horses six months' protection from the fatal bat-borne illness.


A group of horses vaccinated at the CSIRO's Geelong Animal Health Laboratory have remained healthy despite being exposed, in a secure setting, to a big dose of Hendra.


Veterinary pathologist Dr Deborah Middleton is hoping the vaccine also passes a 12-month test.


"A lot of vaccines are given with an annual booster and that sort of regularity is tolerated by the industry, so it's the 12-month data that will also be very important, but after that period of time it's unlikely we'd look for years and years and years."

(Continue . . . )


Hendra first came to light after the deaths of 13 horses and their trainer in Hendra, a suburb of Brisbane, Australia in 1994. A stable hand, who also cared for the horses, was hospitalized, but survived.


Another outbreak was later identified as having taken place in MacKay, 1000 km to the north of Brisbane, the month before. Two horses died, and the owner was hospitalized several weeks later with meningitis. He recovered, but developed neurological symptoms and died 14 months later.


Over the past 18 years more than 40 outbreaks of Hendra virus – all involving horses – have been reported in Australia.  Four human deaths have been recorded as well.


Compared to Nipah, another Henipavirus of the same family (Paramyxoviridae) found in Asia – one that has killed hundreds and has demonstrated a limited ability to spread from human-to-human - Hendra would seem to be less of a public health concern.


Nevertheless, the World Health Organization, along with other researchers, continue to watch this virus carefully for any signs of change.  This from the WHO Hendra FAQ.


Although Hendra virus has caused only a few outbreaks, its potential for further spread and ability to cause disease and death in people have made it a public health concern. The concern has heightened in the most recent outbreaks, as the horses’ symptoms have shifted to become largely neurological instead of respiratory. This suggests the possibility of genetic diversity in the strain, and potentially a more infective virus.