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Why Do we Fall Ill — Science STD 9 — Question

Gujarat BoardEnglish MediumSTD 9ScienceWhy Do we Fall Ill5 Marks
Question
Explain in detail about vaccination along with its history.
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Answer

A vaccination is a treatment which makes the body stronger against a particular infection. The body fights infections using the immune system, which is made up of millions upon millions of cells including $T$ cells and $B$ cells. An important part of the immune system is that it is much stronger when fighting a disease which it has already fought against before. Vaccination involves showing the immune system something which looks very similar to a particular virus or bacteria, which helps the immune system be stronger when it is fighting against the real infection. There are different types of vaccines:
  1. Inactivated vaccines: contain particles (usually viruses). These have been grown for the purpose. They have been killed, using formaldehyde or by other means. But the virus still looks intact; the immune system can develop antibodies against it.
  2. Attenuated vaccines: contain live viruses, that have been weakened. They will reproduce, but very slowly, making it an "easy win" for the immune system. Such vaccines cannot be used on patients with a severely weakened immune system, such as those with $AIDS,$ as they are unable to defeat even this very weak virus.
  3. Subunit vaccines: show antigens to the immune system, without introducing virus material.
HISTORY BEHIND VACCINATION: The first vaccination ever was for smallpox. In $1796$ an English doctor, Edward Jenner, noticed something. He saw that people who got cowpox did not get sick from smallpox. He gave a young boy the cowpox virus to protect him from smallpox. This was done by scratching liquid from cowpox sores into the boy's skin. This same method using liquid from sores was also used to give people smallpox. People did this so they might get smallpox on one place on their body. Then they could pick which body part got scars from smallpox. But sometimes people who did this got very sick from smallpox. Some even died. This was a dangerous thing to do. But people did it because it was less dangerous then getting smallpox. Edward Jenner gave the boy cowpox in the same way people tried to give smallpox. Six weeks later, he scratched smallpox into the boy's skin. The boy did not get sick from smallpox. This boy was the first person ever to get a vaccination. It was not almost $100$ years after the smallpox vaccination the medicine was found the next vaccination for cholera in $1879.$ After that, vaccines for $28$ different types of diseases have been found.

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