1. Viruses and Vaccines
And Antibodies

2. Polio

3. Measles

4. Diphtheria

5. Smallpox

6. Rubella

8. A. Vaccines and how they work
1. The immune system responds in different ways to fight off pathogens
• a pathogen is a living organism or non-living particle which cause an infectious disease

9. Viruses and Vaccines
When a pathogen causes an immune response, it is known as an­­­­­­­­­­­­­­­­­ antigen
An antigen is any substance stimulating production of antibodies
Antibodies combine with antigens to promote their being phagocytized by a macrophage.

10. However, active immunity is often induced when a person is well so that future infection is prevented through immunization
Immunization uses vaccines to provide the antigen to which the immune system responds.
To prepare vaccines, usually pathogens are treated so they are no longer virulent (Can cause disease).

11. Viruses and Vaccines
Vaccines work by mimicking what happens during natural infection without causing illness.
Use altered versions of viruses or bacteria to trigger an immune response.
The immune system recognizes the vaccine as foreign and makes an immune response to it.

12. Viruses and Vaccines
Antibodies are specific to the vaccine and have the ability to remember it, so that if the vaccine or a very similar antigen is seen again, the immune response will be stronger and faster thereby protecting the person from infection.

13. Viruses and Vaccines Vaccines are made by: weakening the virus
inactivating the virus
Using part of the virus or bacteria
Inactivating a toxin made by the bacteria