What is the primary role of adjuvants in vaccines?

• A. They provide additional antigens
• B. They enhance the magnitude and duration of the immune response
• C. They slow the immune response
• D. They reduce side effects of vaccines

Answer: (B)

Adjuvants boost how the immune system reacts to the vaccine. Their main job is to enhance both the strength (magnitude) and the duration of the immune response to the presented antigen. They do this by activating innate immune sensors and improving how the antigen is taken up and shown to immune cells, which leads to stronger antibody and T cell responses and often longer-lasting protection. This can also allow using smaller amounts of antigen or fewer doses while still achieving good immunity. Adjuvants are not mainly about adding extra antigens themselves, they don’t slow down the immune response, and they don’t inherently reduce side effects (they can even cause more local reactions in some cases, though overall protection is improved).