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Summary
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According to government disease-control policy for avian influenza, the animal drug inspection branch is responsible for executing inspections of avian influenza inactivated vaccines derived from H5 and H7 subtypes. Between 2005 and 2010, 17 batch vaccines of H5 subtype and 13 batches of H7 subtype were inspected, including characteristics, sterility, preservative content, safety, HI titer and virus inactivation conformed to the required standards. In which, the HI titer were considered to be the most important in determining vaccine performance. These were evaluated using regulations of USDA-APHIS-VS-CVB as a comparative template. Based on our results, we found, if we used the USDA-APHIS-VS-CVB standard- a HI titer of 32x of 80 % vaccinated chickens (rather than the 16x standard), the percentage of tested vaccine batches reaching standard titers was altered. We found that only 70 % (21/30) reached standard titers at 3 weeks after vaccination, and the remaining 30 % (9/30) did not induce HI titer responses conforming to standard (32x) until 4 weeks after vaccination.
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