What is the route of administration for the hepatitis A vaccine?

• A. Intravenous
• B. Subcutaneous
• C. Intramuscular
• D. Oral

Answer: (C)

The route being tested is how the vaccine is delivered to stimulate the immune system. The hepatitis A vaccine is given by intramuscular injection. Injecting into muscle, usually the deltoid, places the antigen where immune cells—like dendritic cells and macrophages—efficiently take up the material and present it to the rest of the immune system. This promotes a strong and reliable antibody response, which is why this route is standard for this inactivated vaccine.

Other routes aren’t used for this vaccine. Intravenous delivery would push the antigen directly into the bloodstream, bypassing the local immune processing that helps build a targeted response. Subcutaneous injections deliver into fat tissue and can yield a different, sometimes weaker, immune response for this vaccine. Oral administration isn’t appropriate here because the formulation is designed for injection and wouldn’t reliably generate the necessary systemic immunity.