Health: The Ultimate Treasure
Immunity and vaccines
Find out how your body fights disease, and how vaccines help it.
Two people live in the same place, yet one falls ill far more often. Why? The body's natural ability to fight disease is called immunity, and it is the job of a special system, the immune system.
As a small child you were given drops or injections against polio, measles, tetanus or hepatitis. These are vaccines.
A vaccine is like a practice drill for your immune system. It shows the body a harmless version of a germ, so the immune system learns to recognise and attack it. If the real germ ever arrives, the body is ready. This protection, built up after meeting a pathogen or a vaccine, is called acquired immunity.
Vaccines are made in different ways:
- from weakened or dead pathogens;
- from harmless parts of a pathogen;
- some newer ones tell our own cells to make a harmless part of the germ, which the immune system then learns to fight.
A tetanus shot, often given after an injury, contains an inactivated bacterial toxin, so the body builds protection without getting the disease.
The first vaccine came from careful watching. Smallpox was a deadly disease that caused blisters and killed millions. A milder disease, cowpox, seen in cows, could also infect people. In the late 1700s the English doctor Edward Jenner noticed that milkmaids who had had cowpox did not catch smallpox.
| Step | What Jenner did |
|---|---|
| observation | milkmaids who'd had cowpox didn't get smallpox |
| hypothesis | something in the pus of cowpox blisters protects people |
| experiment | he put cowpox material into a boy |
| result | the boy did not fall ill when later exposed to smallpox |
| application | vaccination, which in the end wiped out smallpox worldwide in 1979 |
India had its own, earlier method: variolation. Material from a smallpox sore was scratched into a healthy person's skin. That gave a mild infection, which built immunity. The people who did it were called teekedaars.
Vaccines are one of the best ways to protect people of every age. But remember: vaccines prevent, they do not cure. They stop a disease before it happens; they cannot treat someone who is already ill. Scientists and doctors test them carefully for safety. And when you are vaccinated, the germ can't pass through you, so you protect the people around you too.
India is one of the world's largest vaccine makers and supplies many countries. Indian vaccine companies played a key role during the COVID-19 pandemic. Maharaj Kishan Bhan played a key role in developing the rotavirus vaccine, which protects children from diarrhoea.
Practise this lesson
Questions that get harder as you improve, a Tutor that helps without giving the answer away, and progress you can see. Free for every learner.
No account, no email address. Opens the real product.