Wageningen Bioveterinary Research (WBVR) has started a trial with bird flu vaccination. In Lelystad vaccines against bird flu of three different pharmaceutical companies are tested. In the trial vaccines against the current H5 viruses are tested in laying hens. "More information about the potential vaccines against bird flu is required before these can be applied in the field," explains bird flu researcher Nancy Beerens. The research is done under commission of the Dutch ministry of Agriculture, Nature and Food Quality.
This first vaccine trial is performed in the animal facilities in the high containment unit of WBVR. The modern vaccines were developed by three different pharmaceutical companies; the tested vaccines are based on different technologies. "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," says 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."
Prolonged bird flu season
The call for a vaccine in the battle against bird flu is getting louder, notes Beerens. "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." For the poultry farmers in The Netherlands this has major consequences. Since October 2021, infected poultry farms were culled, transport restrictions were in place and flocks were kept indoors to prevent infection.
Solution against bird flu
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", explains 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."
The bird flu vaccination research at WBVR is the first step in research aimed to combat bird flu with vaccination. The information obtained from this research will be used for future research, such as a field trial.