Determination and Analysis of Viable Count of Live Attenuated Anthrax Vaccine for Percutaneous Scarification

Objective To optimize the condition for transport of live attenuated anthrax vaccine and the determination method for viable count.Methods The viable counts of live attenuated anthrax vaccine for percutaneous scarification submitted by the manufacturers under various transport conditions were determined by plate counting.The vaccine transported at normal temperature for 3 d was determined by sampling using measurable pipette.However,even batches of vaccine transported at low temperature for 6 h were determined using measurable pipette and pipettor separately,and one batch using the two tools for 5 times separately.The precisions of determination results by using measurable pipette and pipettor were compared.Results All the seven batches of vaccines transported at normal temperature were unqualified in viable counts.However,the viable counts of vaccines transported at low temperature were qualified and significantly higher than those transported at normal temperature(P 0.01).The determination results by using measurable pipette and pipettor showed no significant difference(P 0.05),of which the coefficients of variation were 11.3% and 23.0% respectively.Conclusion Live attenuated anthrax vaccine shall be transported at low temperature during submission to control tests.Sampling by pipettor for viable counting was precise and easy to handle,which was benefit to the quality control of vaccine.