Which type of immunity is provided by vaccines?

Vaccines provide active immunity, which occurs when exposure to a disease antigen triggers the immune system to produce antibodies. This process can lead to both a primary immune response and memory cell formation, which enables the body to recognize and fight off the infection more effectively in the future.

With vaccines, a harmless part or a weakened version of the pathogen is introduced to the body, prompting an immune response without causing the disease. As a result, the immune system creates specific antibodies and memory cells targeting that pathogen, thus preparing the body for potential future infections. This immunity can last for years or even a lifetime, depending on the type of vaccine and the pathogen involved.

Passive immunity, in contrast, occurs when antibodies are transferred from one individual to another, such as from mother to baby through breast milk. Natural immunity refers to the immunity developed through natural exposure to pathogens, while innate immunity is the body's first line of defense, comprising physical barriers and immune cells that are always present and ready to respond to infections. Thus, the characteristic of vaccines activating the immune system to generate a long-lasting defense is what classifies it as active immunity.