What vaccines are typically stored in a freezer?

The measles, mumps, rubella (MMR) vaccine and the varicella (chickenpox) vaccine are typically stored in a freezer due to their temperature-sensitive nature. These live attenuated vaccines require strict temperature control to maintain their efficacy. Storing them at freezing temperatures helps preserve the viability of the live virus components.

In contrast, the other vaccines mentioned in the other choices either do not require freezing or are typically stored in a refrigerator. For example, the Hepatitis B and flu vaccines are usually stored in a refrigerator rather than a freezer. Other vaccines like DTAP and those for tetanus and pertussis also have specific storage guidelines that do not typically involve freezing. Thus, the requirement for the MMR and varicella vaccines to be kept frozen sets them apart, confirming that option B is the correct choice.