A trial to protect birds against avian influenza with vaccination has begun by Wageningen Bioveterinary Research (WBVR).
Vaccines against bird flu made by three different pharmaceutical companies against the current H5 viruses are being tested in laying hens. “More information about the potential vaccines against bird flu is required before these can be applied in the field,” said bird flu researcher Nancy Beerens. The research wase commissioned by the Dutch ministry of Agriculture, Nature and Food Quality.
“In this trial we test the effect of the vaccines on clinical signs of disease. Furthermore, the effectivity of the vaccines against the spread of the virus is an important parameter of the study,” said Beerens. “The trial will run for about three months after which data will be analysed. We don’t expect the final results before the second half of December.”
The call for a vaccine in the battle against bird flu is getting louder, Beerens said. “Previously, our summers were free of bird flu infections. This year, for the first time ever, the virus didn’t leave the Netherlands with the migrating birds during springtime. The virus was able to infect birds which stay in our country during summer. This means that the virus is still spreading via bird droppings from infected birds and therefore poultry farms were still infected.”
Vaccination of poultry flocks has many pros and cons. “Bird flu vaccines have to protect against disease but also need to prevent the spread of the virus. If a vaccinated flock gets infected with bird flu but the birds show no signs of illness, a farmer wouldn’t notice the virus infection. If, in that case the vaccine is not effective enough in reducing virus transmission, this could potentially cause ‘silent’ spread of the virus between farms,” said Beerens. This aspect is one of the reasons why the European Union has rules in place for vaccinated poultry.
“We expect that the new types of vaccines we are testing in this trial, provide better protection against the spread of the virus than previous vaccines. Furthermore, it is possible to distinguish between vaccinated and infected animals with specific diagnostic tests.” Several European countries have started bird flu vaccination studies. “The results of these studies are very important for preparing future European agricultural policy which possible allow vaccination of poultry.”