Effects Of Thawing Temperature And Syringe Size On Cell Integrity Of Cell-Associated VAXXITEK® HVT+IBD Frozen Vaccine

Stéphane Lemiere, Anne Bollart & Andreas Herrmann

 

Two questions on frozen cell-associated Marek’s vaccine preparation were raised: temperature of thawing of the frozen ampoules in water bath; recommended temperature by Merial is around + 27°C; does a higher temperature ensure a higher safety for cell integrity? Temperatures of + 30°C and + 33°C were tested as well as + 27°C used as reference, and size of the syringe used to pump out of the thawed ampoules the vaccine suspension to inject into the diluent bag; a large syringe with a volume of 5 mL may have more harmful effect on cell integrity than a smaller one containing 1 mL; question that was raised was about the impact of turbulences induced by the flow of thawed vaccine pushed out of two different sizes of syringes, through the same size of needle. All the mean percentages of cell mortality were comprised between 5% and 12% in this study. The overall trend was an increase during the time of cell mortality in most conditions of temperature either using 1-mL or 5-mL syringes. Effect of temperature of thawing when vaccine preparation was performed with a 1-mL syringe, was noticed for the lowest temperature of + 27°C with a trend to some advantage in recommending this temperature, as target temperature for smoother and more progressive thawing conditions. This was not confirmed with the vaccine prepared with the 5-mL syringe. Effect of choice of syringe equipped with the same needle gauge, whatever the temperature conditions, was noticed for the smallest volume of 1 mL with a trend to some advantage in recommending this volume, for less turbulent vaccine flow inside the needle.

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