What is immunity

Immunity refers to an effective, natural defense system that protects the body against diseases. It distinguishes harmful foreign substances from the body's own components, prevents damage to bodily cells, enhances disease resistance, and thereby maintains health. The mechanism of the immune system involves two primary functions: first, the body's immune system can recognize and destroy bacteria, viruses, and other microorganisms harmful to the host; second, the body can identify and eliminate harmful substances within its own cells. Furthermore, the human immune system can be divided into anti-infective immunity and antiviral immunity. Anti-infective immunity refers to the body’s ability to resist bacteria and fungi, while antiviral immunity refers to its ability to combat viruses. In summary, immunity is a natural protective mechanism against external threats. Its role is to strengthen the body's resistance, reduce damage from harmful external agents to body cells, and ensure overall health.