What does "secondary infection" refer to?

The term "secondary infection" specifically refers to an infection that occurs when opportunistic pathogens take advantage of the weakened immune system following a primary infection. During the course of a primary infection, the body's defenses may be compromised, leaving it vulnerable to other pathogens that would normally be kept in check by the immune system. These opportunistic infections can occur in various ways, often manifesting after the initial illness has destabilized the host's normal defenses.

In a clinical context, this is important because it highlights the need for careful monitoring and management during and after a primary infection. Secondary infections can complicate recovery and potentially lead to more severe health issues. This definition helps in understanding the progression of diseases and the potential complications that can arise during the course of an illness.