Which injection route involves administering into the dermal layer of the skin for vaccines?

Which injection route involves administering into the dermal layer of the skin for vaccines?

• A. Intramuscular (IM)
• B. Intradermal (ID)
• C. Oral
• D. Rectal

Answer: (B)

Injecting into the dermal layer means placing the vaccine just under the outer skin, into the dermis. This route—intradermal—targets the skin’s abundant antigen-presenting cells, like Langerhans cells, allowing even small amounts of antigen to trigger a strong immune response. That’s why vaccines given intradermally use tiny volumes and a very shallow insertion. It contrasts with intramuscular injections, which deposit vaccine deeper into muscle tissue, and with oral or rectal routes, which involve mucous membranes or the GI tract rather than skin. An example of this route’s use is the tuberculin skin test, which relies on intradermal administration to elicit a visible reaction.

Injecting into the dermal layer means placing the vaccine just under the outer skin, into the dermis. This route—intradermal—targets the skin’s abundant antigen-presenting cells, like Langerhans cells, allowing even small amounts of antigen to trigger a strong immune response. That’s why vaccines given intradermally use tiny volumes and a very shallow insertion. It contrasts with intramuscular injections, which deposit vaccine deeper into muscle tissue, and with oral or rectal routes, which involve mucous membranes or the GI tract rather than skin. An example of this route’s use is the tuberculin skin test, which relies on intradermal administration to elicit a visible reaction.