Definition of immunity

The word "immunity" originated from the Latin word "immunitas," meaning freedom or exemption. In the 14th century, the term was adopted by the legal field to refer to the exemption of certain individuals or groups from legal penalties or obligations. However, it was not until the 19th century that the term was used to describe the biological concept of immunity, specifically the body's natural ability to resist disease or infection. The concept of immunity in the medical field came from Edward Jenner's discovery in 1796 of the smallpox vaccine. He noticed that milkmaids who contracted cowpox, a mild virus, seemed to be immune to smallpox. This led to the idea that introducing a milder virus in order to generate immunity against a serious one could be a useful medical concept. Over time, the scientific understanding of immunity has expanded to encompass both innate and adaptive immunity, including the role of white blood cells, antibodies, and vaccines in protecting the body from harm. Today, "immunity" refers specifically to the ability of an organism or individual to resist infectious diseases or other potentially damaging substances.