A vaccine is a medicine that makes a person less likely to get a disease. It gives immunity to an infectious disease caused by a particular pathogen.
What is Vaccination?
Vaccination is the administration of a vaccine to help the immune system develop protection from a disease.
Mechanism of Vaccination
Let us understand this with the help of an example.
Polio vaccine: Polio drops have a weakened form of the poliovirus. The virus administered is too weak to affect the human body, but it does help the human immune system to recognize this virus and fight it. When we are vaccinated with the polio vaccine our body becomes immune to polio and we are safe from this disease. So when the actual poliovirus enters our body, our body recognises the virus and fights it off.
History of vaccines and vaccination
It was Edward Jenner, an English physician who discovered this technique. About two centuries ago, Jenner found that during an epidemic of smallpox, a deadly disease back then, some milkmaids did not contract this disease. On further research, he realized that these maids had a common history of the cowpox disease.
The virus of cowpox is very similar to that of smallpox, and therefore their body had already developed a fighting mechanism. If the smallpox virus enters the body of the maids, the body recognizes it and kills it.
Jenner decided to test this discovery. So he deliberately gave the cowpox virus to healthy individuals and these individuals then became immune to smallpox. This is how he found a way to be safe from the smallpox disease.