A hypersensitivity reaction occurs
A) during the first exposure to an antigen.
B) during a second or subsequent exposure to an antigen.
C) in individuals with diseases of the immune system.
D) only in children.
E) only in individuals with asthma.

Question

Quizplus · Accepted Answer

Hypersensitivity reactions occur during a second or subsequent exposure to an antigen, as the immune system has already been sensitized to it.

A Hypersensitivity Reaction Occurs