China is most likely using substandard poultry vaccine or not enough good vaccine, which would explain recent outbreaks of the deadly H5N1 bird flu virus in poultry, a prominent virologist said on Thursday.
[...] "If you use a good vaccine you can prevent the transmission within poultry and to humans. But if they have been using vaccines now (in China) for several years, why is there so much bird flu?" Webster told Reuters in Hong Kong.
"There is bad vaccine that stops the disease in the bird but the bird goes on pooping out virus and maintaining it and changing it. And I think this is what is going on in China.
"It has to be. Either there is not enough vaccine being used or there is substandard vaccine being used. Probably both."
Webster praised China's ambitious plan to vaccinate all its chickens, but also called for agricultural vaccines to be standardized.