A leading virologist has indicated that China might be using "substandard poultry vaccine", which could be the reason why there were frequent and deadly outbreaks of bird flu in that country.
Dr Robert Webster, of St Jude's Children's Hospital in Memphis, Tennessee, however said that this problem was not confined to mainland China alone. "It's not just China. We can’t blame China for substandard vaccines. I think there are substandard vaccines for influenza in poultry all over the world," he said. "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?" He added that the reason could be that the birds go on spewing out the virus into the environment all the while changing the basic structure of the virus thus facilitating its continued spread. "It has to be. Either there is not enough vaccine being used or there is substandard vaccine being used. Probably both."Dr Webster said that while China's pledge to vaccinate all chickens is to be welcomed, it must be ensured that agricultural vaccines were standardized. "If you go back to 1918, it showed that there are about 10 critical amino acids in that virus that seemed to be necessary (for the virus) to be pathogenic," Webster said, adding that the H5N1 virus was beginning to show the same characteristics like the Spanish flu virus that had killed 50 million people. "It is important to realize that the H5N1 cases in China recently are also sensitive to the old-fashioned drugs amantadine and rimantadine. So we need to be thinking more about combinations of these drugs, combinations of amantadine, rimantadine and Tamiflu," he concluded.
