Vaccines against avian influenza
According to Nancy Beerens, the head of the National Reference Laboratory for avian influenza, two out of four vaccines tested for their efficacy against highly pathogenic avian influenza (HPAI) type H5N1, are effective under laboratory conditions.
The HVT-H5 vaccines prevent the spread of the virus and protect against disease symptoms in laying hens. The study was conducted at Wageningen Bioveterinary Research, in collaboration with Utrecht University, Royal GD, and Wageningen University & Research, on behalf of the Dutch Ministry of Agriculture, Nature and Food Quality.
The study involved testing three modern vaccines in laying hens, including the HVT-H5 vaccines from Ceva Sante Animale and Boehringer Ingelheim Animal Health, and a DNA vaccine from Huvepharma. An older vaccine called Nobilis from Merck Sharp & Dome was also included. The HVT-H5 vaccines were found to be 100% effective in preventing disease and mortality after infection with the HPAI H5N1 virus and preventing virus spread between chickens.
The selected vaccines comply with the DIVA principle, which allows distinguishing between animals that have been vaccinated and animals that have produced antibodies due to bird flu infection. The HVT-H5 vaccines are already on the market in other countries or are in an advanced stage of development. However, further research is needed to investigate whether the vaccines work well under field conditions in poultry farms, how long the vaccines protect, and whether one vaccination is sufficient.
The Dutch Ministry of LNV has commissioned a field study, which will begin in the summer, to investigate the effectiveness of the vaccines under field conditions. The vaccines also need to be registered in the Netherlands and the European Union. Despite the hurdles, the results of the study are an important first step towards vaccination against the avian influenza virus in poultry.
