In which population is an intradermal injection most commonly used?

Intradermal injections are a method of administering vaccines and medications where the injection is made into the dermis, just below the epidermis. This route is particularly advantageous for specific vaccinations and allergy tests, as it allows for a small volume of substance to be delivered.

The correct answer involves acknowledging that intradermal injections are utilized across all age groups, including infants, children, and adults. This method can effectively provide immunization, desensitization, or other therapeutic outcomes regardless of the recipient's age.

In infants, an example of an intradermal injection is the tuberculosis (TB) skin test, which is crucial for assessing exposure to tuberculosis. In children and adults, it can be used for the same TB tests or for vaccines such as the flu vaccine in certain formulations. Thus, intradermal injections play a critical role in healthcare across all populations, making their use relevant in any age group.