Clinical Guidance on the Use of Live Attenuated Influenza Vaccine After Inadvertent Freezing and Warming 1

The immediate and long-term impact of temperature deviations that may occur in clinical practice on live attenuated influenza vaccine (LAIV) potency was examined in four distinct studies that exposed vaccine to freeze/thaw cycles, warming, and heating conditions. No significant loss of vaccine potency was observed after three freeze/thaw cycles, warming of vaccine to 15°C (59°F) for 72 hours or less, exposure to room temperature (25°C/77°F) for 12 hours or less, or after heating to 37°C (99°F) for 6 hours or less. The results of these studies demonstrate that LAIV potency can potentially be maintained after exposure to temperature deviations. If a particular annual formulation of LAIV is exposed to temperatures outside of the recommended storage range, practitioners should contact the manufacturer for guidance regarding proper vaccine handling.