Barbervax, the first commercially available defined antigen vaccine for any parasitic nematode, was registered in Australia in October 2014.
Barbervax is an unusual vaccine for three reasons.
First, it consists of antigens which are not recognized by the host during infection – they are so-called hidden antigens, a feature which has advantages and disadvantages.
Second, the vaccine antigens are native, purified from adult Haemonchus harvested on a large scale from donor sheep.
Third, the vaccine is made by the Moredun group in Australia. No large pharmaceutical company is involved.
The vaccine has now been evaluated in more than 30 field trials in Australia, South Africa, Brazil, Uruguay, Switzerland or Mexico and in goats and calves as well as sheep. The antigens, which are extracted from the brush border of H. contortus intestines, appear to be conserved. Thus vaccine made in one country protects in another, and even against H. placei, a different species.
The biochemical characteristics of the major antigens in Barbervax will be outlined briefly, the methods used for large-scale vaccine manufacture described and selected field trial results presented.
Barbervax has now been used in some 250,000 Australian lambs in North East New South Wales during the two seasons it has been commercially available. Clients were provided with free egg counting kits so that vaccine performance could be monitored. There was sufficient rain to ensure a strong parasite challenge in both seasons. The performance of Barbervax under the conditions that prevailed will be reported.