Should avian influenza vaccines be made available? Experts say high-level biosecurity management in poultry houses is most important
At the end of last year, Taiwan, China experienced the most severe avian influenza outbreak in its historyand there were even reports of some secretly vaccinating their flocks. Despite considerable calls to open up vaccine use, even pharmaceutical experts pointed out that in avian influenza control strategies, vaccines are merely a tool: "Vaccination accounts for only ten percent of disease prevention; the other ninety percent lies in establishing poultry houses with high biosecurity and management strategies."
The Mixed Blessings of Avian Influenza Vaccination
Last Friday, the Central Livestock Production Association, a foundation, held the "Taiwan Poultry Health and Disease Prevention Seminar," inviting experts from internationally renowned animal pharmaceutical companies such as Intervet, Boehringer Ingelheim, and the French company Ceva. Besides developing vaccines for common diseases like Newcastle disease and infectious bronchitis, these companies have also been investing in avian influenza vaccines. They unanimously stated that avian influenza vaccination can coexist with culling.
Lin Yueh-chun, technical manager of Taiwan Intervet Animal Health Company, stated that vaccinating against avian influenza can raise the threshold for infection; the dose required to infect a vaccinated flock needs to be 100 times higher than at present. If vaccinated chickens become infected, their virus shedding will also be 100 times lower than that of unvaccinated chickens.
Aris Malo, Boehringer Ingelheim's global poultry technical director, also pointed out that vaccines can be administered by surrounding the epidemic area. For example, within 5 kilometers of an outbreak site, culling and movement controls are implemented, while within 20 kilometers, vaccination is carried out to prevent the spread of the epidemic. At the same time, however, strict monitoring plans must be coordinated to prevent vaccinated chickens that become infected from causing misjudgment by disease prevention personnel because they show no symptoms.
Farmers Secretly Vaccinating? Council of Agriculture: Already Cooperating with Prosecutors and Investigators
Regarding the experts' recommendations, Shih Tai-hua said bluntly that poultry farms are now required to adopt enclosed or non-open poultry houses, and "I believe the epidemic can be controlled." As for suspected secret vaccination by farmers, he said cooperation with prosecutors and investigators is already underway, but no information can be disclosed at this stage.
However, such optimistic statements were immediately challenged by foreign experts on the spot, who pointed out that Taiwan, China has been culling for over a decade and still cannot eradicate the disease, showing that there is room for improvement in policy implementation and control, and that public awareness needs strengthening.