SUBJECT: BASIC SCIENCE
TOPIC: IMMUNITY AND IMMUNIZATION
CLASS: JSS 1
CURRICULUM: NIGERIAN (NERDC)
1. Introduction
Our environment is full of tiny organisms called pathogens (germs) such as bacteria, viruses, and fungi that can cause diseases. However, the human body has a special defense system that fights these germs to keep us healthy. This defense system is known as Immunity.
2. What is Immunity?
Immunity is the ability of the body to resist or fight off diseases caused by germs. It is like having a "security guard" or "soldiers" inside your body that identify and destroy harmful invaders.
Types of Immunity
- Natural (Innate) Immunity: This is the protection you are born with. It includes the skin (which acts as a barrier) and special cells that attack germs immediately. It also includes immunity a baby gets from its mother through breast milk.
- Acquired (Artificial) Immunity: This is the protection the body develops over time. It can happen after you have already suffered from a disease (the body "remembers" how to fight it) or through immunization.
3. What is Immunization?
Immunization is the process of making a person immune or resistant to an infectious disease, typically by the administration of a vaccine.
- Vaccine: A vaccine is a biological substance (usually made from weakened or killed forms of the germ) that is introduced into the body to stimulate the body’s immune system to recognize and fight a specific disease in the future.
4. How Immunization Works
- A vaccine is given (usually by injection or drops in the mouth).
- The body's immune system sees the vaccine as a "training exercise."
- The body produces antibodies to fight the weakened germs in the vaccine.
- If the real, strong disease germ ever enters the body later, the immune system "remembers" it and destroys it before it can make the person sick.
5. Common Diseases Preventable by Immunization
In Nigeria, the National Programme on Immunization (NPI) ensures that children are protected against many dangerous diseases. These include:
- Tuberculosis (TB): Prevented by the BCG vaccine.
- Poliomyelitis (Polio): Prevented by the OPV (Oral Polio Vaccine). It causes paralysis.
- Measles: Prevented by the Measles vaccine. It causes skin rashes and high fever.
- Whooping Cough (Pertussis): Prevented by the DPT vaccine.
- Tetanus: Also prevented by the DPT vaccine.
- Hepatitis B: Protects the liver.
- Yellow Fever: A disease spread by mosquitoes.
6. Importance of Immunization
- Saves Lives: It prevents children from dying from diseases that can be easily avoided.
- Prevents Disability: Vaccines like the Polio vaccine prevent permanent lameness or physical disability.
- Healthy Growth: Immunized children grow up healthier and stronger because their bodies aren't constantly fighting severe illnesses.
- Eradication of Disease: When everyone is immunized, a disease can disappear completely (e.g., Smallpox was wiped out globally through immunization).
- Saves Money: It is much cheaper to prevent a disease with a vaccine than to treat a very sick person in the hospital.
7. Summary
- Immunity is the body's power to resist disease.
- Immunization is the act of giving vaccines to protect the body.
- Vaccines are the "medicines" used for immunization.
- Prevention is better, safer, and cheaper than cure.
Review Questions
- Define Immunity.
- What is the difference between Natural and Acquired immunity?
- Explain how a vaccine works in the body.
- List four diseases that can be prevented through immunization in Nigeria.
- Why is it important for every child to complete their immunization schedule?
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