Vaccine
3 Minutes
Vaccines for kids: learn how antibodies protect the body, how Edward Jenner created vaccines, and examples like BCG and MMR. An English science lesson.
- How soldier-like antibodies protect our body from diseases
- Edward Jenner testing cowpox to discover the smallpox vaccine
- How BCG and MMR vaccines train antibodies with weakened germs
What this lesson teaches
A vaccine is a medical preparation made from dead or weakened microorganisms that teaches the human body to protect itself against disease. It allows the body to build defense before a stronger illness can cause harm.
How antibodies protect the body
Inside the human body, substances called antibodies act like army soldiers defending against intruders. Whenever harmful microorganisms or disease-causing substances enter the body, these antibodies fight them and push them out. While microorganisms like bacteria, viruses, and fungi can cause dangerous illnesses, they are also useful in agriculture, industry, and medicine. In medicine, they are used to create vaccines and antibiotics that help our bodies survive infections.
The discovery by Edward Jenner
- Long ago, people in a village were suffering severely from an illness known as smallpox (periyammai).
- A man named Edward Jenner noticed that people who worked on dairy farms and raised cows never caught smallpox.
- He suspected that these farm workers were protected because they had already suffered from an illness called cowpox.
- To test his theory, Jenner injected the cowpox virus into an eight-year-old boy, who caught cowpox but fully recovered after a few days.
- Two months later, Jenner injected the smallpox virus into the boy, and the boy did not get smallpox, proving how vaccination could protect a person.
How vaccines train the memory
Vaccines work by introducing killed or weakened forms of a disease-causing microorganism into the body. Because the introduced germs are weak, the antibodies can easily fight them off and store a memory of the battle. The body keeps this memory so it knows exactly how to fight if that germ ever returns. If the same microorganism attacks later in a much stronger form, the antibodies recognize it immediately, fight it off, and easily push it out.
Common examples of vaccines
- The BCG vaccine is given during childhood to prevent an infection called tuberculosis, and it often leaves a mark on the left hand.
- This vaccine is prepared from the bacteria named Mycobacterium tuberculosis so that the body is protected if the bacteria enters in the future.
- The MMR vaccine is another important medicine that protects children from three different diseases: measles, mumps, and rubella.