WHAT IS IMMUNITY?

Immunity is the body’s natural ability to protect itself against infections and diseases caused by harmful agents such as bacteria, viruses, fungi, and toxins. It works through a coordinated system of organs, cells, and molecules—collectively called the immune system—that recognize and eliminate threats.

Simple definition

👉 Immunity = the body’s defence mechanism that helps you stay healthy and fight infections

How immunity works

The immune system:

• Identifies foreign invaders (pathogens)
• Responds to destroy or neutralize them
• Remembers past infections to respond faster in the future

Types of immunity

1. Innate immunity (natural immunity)

• Present from birth
• Acts as the first line of defense
• Fast but non-specific

Examples:

• Skin and mucous membranes
• Stomach acid
• White blood cells (like neutrophils)
• Inflammation and fever

2. Adaptive immunity (acquired immunity)

• Develops after exposure to pathogens or vaccines
• Highly specific and long-lasting

Examples:

• Antibodies
• T cells and B cells
• Immune memory after infection or vaccination

3. Active immunity

• Your body produces antibodies itself
• Comes from infection or vaccination
• Long-lasting

4. Passive immunity

• Antibodies are received from another source
• Short-term protection

Examples:

• Antibodies from mother to baby (breast milk)
• Antibody injections

Why immunity is important

• Prevents frequent infections
• Reduces severity of illness
• Supports faster recovery
• Protects against chronic diseases and complications

Factors that affect immunity

• Nutrition (vitamins A, C, D, E, zinc, selenium)
• Sleep quality
• Stress levels
• Physical activity
• Age and lifestyle habits