Vaccination and Pathogens

HIV is a virus. A virus is a pathogen that can cause disease. Some pathogens such as influenza (flu) measles, mumps, rubella and chickenpox can be vaccinated against. This means that by receiving a vaccination against this virus, the person has immunity to the disease. Different vaccines are needed for different pathogens.

• Have you been vaccinated against any diseases?
• When and why?
• Did you suffer a reaction?

Vaccination entails injecting a small amount of an inactive form of a pathogen, or dead pathogen, into the body. Try to complete this TRUE/FALSE activity to show what vaccines can contain:

The elements identified as TRUE all act as antigens. When injected into the body, they stimulate white blood cells to produce antibodies against the pathogen.

The vaccine only contains a harmless version of a pathogen so the vaccinated person is not in danger of developing disease - although some people may suffer a mild reaction. If the person becomes infected by the pathogen later in their life, the required lymphocytes (white blood cells) are able to quickly reproduce and destroy it.

The next activity will help you to understand why it is so hard to find a vaccine to protect against HIV.