Stabilizing cold-adapted influenza virus vaccine under various storage conditions.

Various diluents, stabilizers, buffers, and storage conditions were assessed for their efficacy in stabilizing cold-adapted influenza virus vaccine. Frozen liquid vaccine formulations, comprised of a normal uninfected allantoic fluid diluent and an SPG (sucrose-phosphate-glutamate) stabilizer, generated complete stability of H1N1, H3N2, and Type B strains for at least 1 year of storage at -20 degrees C. The ability to store live influenza virus frozen liquid vaccines, at the moderate temperature of -20 degrees C, has not been demonstrated previously. This significant advance could facilitate influenza vaccine storage and administration in the clinic, and subsequently increase marketability. The stability of lyophilized formulations was also augmented by the addition of 2% Casitone and the control of pH with 0.066 M phosphate in the SPG stabilizer. This alternative formulation may be useful in markets where freezing is not feasible or short-term room temperature storage is necessary.