What is the term used for the practice of using dried crusts from smallpox pustules to induce immunity?

The practice of using dried crusts from smallpox pustules to induce immunity is referred to as variolation. This method involved taking material from the pustules of individuals who had a mild case of smallpox and introducing it into a healthy person, often through a scratch in the skin. The goal was to provoke a mild form of the disease, leading to immunity without the severe complications associated with a full-blown case of smallpox.

Variolation was one of the earliest forms of immunization and laid the foundation for the development of modern vaccination techniques. By intentionally exposing a person to the virus in a controlled manner, variolation helped to create a safe form of immunity and significantly reduced mortality rates from smallpox in populations where it was practiced.

In contrast to this process, vaccination specifically refers to the introduction of a vaccine—often a harmless component of the pathogen (like a weakened or inactivated form of a virus) rather than actual infectious material. While both practices aim to induce immunity, they are distinctly different in method and execution. Immunotherapy generally pertains to treatments designed to boost or manipulate the immune response and does not specifically imply using an infectious agent. Lastly, inoculation is a broader term that could encompass variolation but is typically used to refer