Which of the following vaccines should be administered subcutaneously?

The MMR (measles, mumps, and rubella) vaccine is typically administered subcutaneously because it is a live attenuated vaccine. Vaccines that are made from live viruses often require subcutaneous injection to ensure that the immune system can adequately respond to the attenuated virus. This route allows the vaccine to be absorbed slowly, providing the appropriate immune response without the risk of causing disease.

Subcutaneous administration is also important for maintaining the integrity of live attenuated vaccines, as they are sensitive to certain environmental factors. By delivering the MMR vaccine subcutaneously, pharmacists and healthcare providers utilize the method that has been historically proven to be effective for this type of vaccine, ensuring optimal immunogenicity while minimizing potential side effects.

In contrast, Tdap (tetanus, diphtheria, pertussis), IIV (inactivated influenza vaccine), and HPV (human papillomavirus) vaccines are typically administered intramuscularly, as these types of vaccines are formulated in a manner that is better suited for that route of administration, allowing for appropriate absorption and immune system activation.