Two bird flu vaccines are being tested in a field study. A scientific field study commissioned by the Dutch Ministry of Agriculture, Fisheries, Food Security and Nature (LVVN) has been running since September 2023 on two laying farms to investigate the effectiveness of vaccination against bird flu. Previous research at the laboratory of Wageningen BioVeterinary Research (WBVR) showed that two vector vaccines were effective under laboratory conditions against clinical signs and spread of high-pathogenic H5 bird flu. 

However, because the effectiveness of a vaccine can be different in a poultry house than in a laboratory, a trial was needed under field conditions. This research is being done by Wageningen University & Research (WUR) including WBVR, Royal GD and Utrecht University’s Faculty of Veterinary Medicine. It commenced in September 2023. 

Field Trial 

In the field trial, 1,800 one-day-old layer chicks were vaccinated against bird flu (H5) to investigate the effectiveness of vaccination under field conditions. During the field trial, challenge transmission tests will be carried out at various ages. For this purpose, a number of chickens will be transported from the farm to WBVR and be exposed to the 2.3.4.4b H5 bird flu virus under laboratory conditions. The first trial, eight weeks after vaccination, showed that the vaccines prevented clinical signs and infection with bird flu virus. The second transmission test took place at 24 weeks of age, the time when hens have just reached their peak production. These results are not yet available. 

It is important to know whether vaccines are effective throughout a laying hen’s production phase. To this end, Photo: (left) Chicks are vaccinated at the hatchery, (right) Vaccine is prepared for use (Royal GD) transmission trials will take place at two further ages: at 54 and 84 weeks of age. The final results will be known in the second half of 2025. 

Third Vaccine in the Picture 

The field trial is taking place over the entire laying period of the chickens, so this takes time. In the meantime, time does not stand still. In the current field trial, vaccines from two manufacturers are being scientifically investigated. Recently, a third manufacturer announced that it has developed a vector vaccine that has received a European approval. This vaccine is an HVT vector vaccine, i.e. the same type as the two vaccines tested in the field trial.