Science
How do vaccines work?
Vaccines work by safely teaching your immune system to recognize a specific germ in advance. They expose the body to a harmless piece or weakened form of the pathogen, so it can build defenses and respond fast if the real one ever appears.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how vaccines works.
Step by step
- 1A vaccine contains a harmless signature of a pathogen — a protein, a weakened version, or instructions to make one.
- 2The immune system reacts, builds antibodies, and creates 'memory' cells.
- 3If the real pathogen later invades, memory cells recognize it and respond much faster.
- 4Widespread vaccination also protects vulnerable people through 'herd immunity.'
Frequently asked questions
- Do vaccines give you the disease?
- No. Most contain only a harmless fragment or a weakened/inactivated form that can't cause the illness but still trains the immune system.
- What are antibodies?
- Proteins the immune system makes to recognize and neutralize a specific pathogen. Vaccines prompt the body to produce them in advance.
- What is herd immunity?
- When enough of a population is immune that a disease can't spread easily, indirectly protecting those who can't be vaccinated.