A DUTCH vaccine study looking at the effectiveness of four vaccines against highly pathogenic H5N1 avian influenza has found two to be effective.

Under laboratory conditions, two vaccines offered protection against both disease symptoms in laying hens and prevented the spread.

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The vaccine study was carried out at Wageningen Bioveterinary Research, part of Wageningen University & Research (WUR), in collaboration with Utrecht University, Royal GD and WUR, on behalf of the Dutch Ministry of Agriculture, Nature and Food Quality (LNV).

Study design

Each vaccine was administered to ten laying hens.

Subsequently, five chickens were infected with the bird flu virus.

These were grouped with the five chickens that were not infected. This study design investigated whether the virus would spread to uninfected chickens.

“Our study shows that both HVT-H5 vaccines are effective under laboratory conditions and prevent both disease and virus spread.

“These vaccines comply with the DIVA principle and are therefore good candidates for further research in practice,” said Nancy Beerens, head of the Netherlands’ National Reference Laboratory for avian influenza.

Field conditions

HVT-H5 vaccines can be administered in the egg or to day-old chicks in the hatchery, and it is possible to distinguish between field and vaccine strains.

The next step is to investigate the vaccines under field conditions, as opposed to a laboratory setting. The Dutch Ministry of LNV has commissioned a field study starting this summer.

In addition, the vaccines still have to be registered in the Netherlands and the European Union.

“There are still some hurdles to overcome, but the results of our research are an important first step towards vaccination against the bird flu virus in poultry,” added Dr Beerens.