What is immunity?

Immunity refers to the ability of the human or animal body to regulate its immune system upon exposure to pathogens, thereby preventing or reducing the impact of these pathogens. Immunity is an effective defense mechanism that detects specific antigens of pathogens to combat their invasion and protect the body from damage, ultimately preventing disease caused by pathogenic attacks. The human body possesses natural immunity, meaning it relies on its own immune system to defend against invading pathogens. Symptoms such as fever, rashes, and erythema are examples of the body's responses in fighting pathogens. If the body's ability to resist pathogens weakens, it becomes more susceptible to infections and diseases. Therefore, timely enhancement of immunity ensures the body maintains sufficient capacity to resist pathogen invasion, thus preserving good health. There are two fundamental types of immunity: specific immunity and non-specific immunity. Specific immunity refers to the body's ability to recognize particular antigens, enabling rapid identification of viruses and effective resistance against pathogen invasion. Non-specific immunity refers to a defense mechanism that does not require specific antigens; it can inhibit or kill microorganisms and reduce pathogen replication.