Which of the following vaccines must be frozen?

Zostavax is a live attenuated herpes zoster vaccine that is specifically recommended to be stored in the freezer and not in a refrigerator. This is essential for maintaining its potency and effectiveness. The vaccine must be stored at temperatures between -50°C and -15°C. Freezing helps preserve the live attenuated virus within the vaccine for optimal immunogenicity, ensuring that it can effectively stimulate an immune response when administrated to patients, usually older adults to help prevent shingles.

In contrast, inactivated influenza vaccines and Tdap vaccine do not require freezing; they are stable at refrigerator temperatures. The live attenuated influenza vaccine, while also a live virus vaccine, is not required to be frozen and is typically stored in the refrigerator instead. Understanding the storage requirements for different vaccines is critical in maintaining their effectiveness, making this knowledge crucial for health care providers involved in vaccine administration.