What Is a Vaccine? When Did Vaccinations Begin?
Vaccine is a substance which is introduced into the body in order to help it build up a resistance or immunity to a particular infectious disease. A vaccine is really a minute amount of the very disease which it is intended to protect against. Very small quantities of the disease cause the body to set up its own defense (called an antibody) against the disease.
Then, should the body ever come into contact with larger quantities of the disease, it is able to fight and defeat the disease before it causes the body any harm. Vaccines can be prophylactic (to prevent or ameliorate the effects of a future infection by a natural or “wild” pathogen), or therapeutic (e.g., vaccines against cancer, which are being investigated).
The administration of vaccines is called vaccination. Vaccination is the most effective method of preventing infectious diseases; widespread immunity due to vaccination is largely responsible for the worldwide eradication of smallpox and the restriction of diseases such as polio, measles, and tetanus from much of the world.
The terms vaccine and vaccination are derived from Variolae vaccinae (smallpox of the cow), the term devised by Edward Jenner to denote cowpox in 1798 in which he described the protective effect of cowpox against smallpox. In 1881, to honor Jenner, Louis Pasteur proposed that the terms should be extended to cover the new protective inoculations then being developed.
Louis Pasteur’s 1885 rabies vaccine was the next to make an impact on human disease. And then, at the dawn of bacteriology, developments rapidly followed. Antitoxins and vaccines against diphtheria, tetanus, anthrax, cholera, plague, typhoid, tuberculosis, and more were developed through the 1930s.
The middle of the 20th century was an active time for vaccine research and development. Methods for growing viruses in the laboratory led to rapid discoveries and innovations, including the creation of vaccines for polio. Researchers targeted other common childhood diseases such as measles, mumps, and rubella, and vaccines for these diseases reduced the disease burden greatly.
Innovative techniques now drive vaccine research, with recombinant DNA technology and new delivery techniques leading scientists in new directions. Disease targets have expanded, and some vaccine research is beginning to focus on non-infectious conditions such as addiction and allergies.