LEARNING TARGETS

Outline the terms such as antigen, antibody, and pathogen

Describe how vaccines prevent the spread of disease

Vaccination involves exposing the body’s immune system to a weakened or harmless version of the pathogen in order to stimulate white blood cells to produce antibodies.

Vaccination

People can be immunised against a pathogen through vaccination. Different vaccines are needed for different pathogens.

Vaccination involves putting a small amount of an inactive form of a pathogen into the body. Vaccines can contain:

• • live pathogens treated to make them harmless

  • harmless fragments of the pathogen

  • toxins produced by pathogens

  • dead pathogens.

These all act as antigens. When injected into the body, they stimulate white blood cells to produce antibodies to fight the pathogen.

The vaccine contains only a weakened or harmless version of a pathogen, which means that the vaccinated person is in no danger of developing the disease. Some people, however, may suffer a mild reaction. If the person later becomes infected with the pathogen, the required (white blood cells) are able to reproduce rapidly and destroy it.

Vaccines and boosters

Vaccinations in early childhood can offer protection against many serious diseases. Sometimes more than one vaccine is given at a time, like the MMR triple vaccine against mumps, measles and rubella.

Sometimes vaccine boosters are required because the immune response ‘memory’ weakens over time. Anti-tetanus injections may need to be repeated every ten years, for example.

Ideas about science - making decisions

There is often a conflict between a person’s right to decide what is best for themselves and their family and what is best for society as a whole. For example, some people used to think the MMR (measles, mumps or rubella) vaccine could cause autism in children. They decided not to risk letting their child have the vaccine and hoped they would not catch any of the three diseases. But this meant that as less and less children were vaccinated the diseases began to spread more easily and the number of cases began to increase. Therefore, a decision originally taken by a number of single individuals had big implications for society as a whole.

Vaccinations can never be completely safe because side-effect levels vary. So, when making a decision, these are some of the factors that should be considered:

• • when fewer people are vaccinated, the number of cases of the disease increases

  • the chance of falling seriously ill or dying from the disease may be far greater than the chance of experiencing a serious side-effect

  • using a vaccine may be much cheaper than treating a very ill person.

Research task:

Pick a disease to research that is caused by a microbe (Bacteria, fungi or virus) and CAN be vaccinated against.

You should include the following:

• Information about the disease - how does it affect the body? Is it a bacteria? A virus?

• How does the vaccination help to combat the disease?

• When was the vaccination first introduced? Who discovered it?

• Has the vaccination been successful? (e.g. is it used worldwide? Are there any serious side effects? Does vaccination make it 100% certain you won't get the disease?)

You must give references for the sources of information you use.

You have up to 35 minutes to do the research and answer the questions. Once you have finished you need to exchange your report with another student in the class. You need to read through each others reports and give them verbal feedback on the following points:

• The extent to which the above questions have been answered

• Clarity of written communication

• The quality of the referencing

YOU MAY WANT TO MAKE YOUR REPORT VISUAL AND ENGAGING