First Chickens Vaccinated Against Avian Influenza in Trial Phase

The first shot has been administered: 1,800 day-old chicks are receiving a vaccination against highly pathogenic avian influenza. Never before have chickens in the Netherlands been vaccinated against avian influenza as part of a field trial. With this field trial initiated on behalf of the Ministry of Agriculture, Nature and Food Quality (LNV), an important step is being taken towards large-scale vaccination of poultry against avian influenza.

Minister Piet Adema said, “Avian influenza is a serious disease that has greatly affected the poultry sector, impacting both the animals and the entrepreneurs, and causing significant harm to wild birds as well. That’s why we are taking action together to reduce the number of infections among domestic poultry.”

Field Trial Previous laboratory research at Wageningen Bioveterinary Research (WBVR) showed that two vector vaccines against highly pathogenic avian influenza were effective in preventing the spread of the virus. The Ministry is now having Wageningen University & Research (WUR), Royal GD (Dutch Animal Health Service), and the Faculty of Veterinary Medicine at Utrecht University investigate whether these two vaccines are also effective in practice.

At the beginning of the field trial, the chicks are divided into different test groups. Over time, a number of chickens from the field trial will undergo testing in the laboratory under controlled conditions to assess their effectiveness against infection. Throughout the trial, the chickens will be intensively monitored and controlled, in accordance with the new European regulation. This field trial is a scientific study, and the products from vaccinated chickens will not be released onto the market. Chickens are already vaccinated against various diseases.

Results The trial on two farms will last until the third quarter of 2025. Initial results are expected in the second quarter of 2024. The effectiveness of a vaccine under practical conditions may differ from that under controlled laboratory conditions. In a poultry barn, for instance, housing and climate conditions are different, animals are vaccinated against more diseases, and there are other microorganisms present that could affect the vaccine’s effectiveness. It is essential that the vaccines not only provide protection against disease symptoms but also prevent the spread of the avian influenza virus.

Vaccination Trajectory The government aims to enable vaccination in a responsible manner, considering animal and public health and animal welfare. Therefore, a step-by-step approach has been chosen. In addition to the field trial, a pilot project will be conducted to vaccinate a larger number of poultry farms in the Netherlands. The pilot is expected to take place in the second quarter of 2024 on multiple poultry farms. A prerequisite is that the vaccine has European approval by then and that the results of the initial laboratory test are known.

The pilot will also focus on the effects of vaccination on the trade in poultry products and the establishment of a surveillance program. This surveillance program aims to quickly detect any potential infection on a vaccinated farm, which could still occur despite vaccination, in order to minimize the chance of the virus circulating.

Vigilance It is still crucial for poultry farmers to remain vigilant and report any suspicion of avian influenza as soon as possible to the Netherlands Food and Consumer Product Safety Authority (NVWA), as they do now, and continue to apply the mandatory hygiene measures. Currently, this is the best way to minimize the risk of avian influenza infection.