In GCSE Biology students will look at how people can be immunised against certain unpleasant, and even deadly, diseases by vaccination. The vaccination process is often referred to as inoculation and has helped to completely eradicate some diseases such as smallpox. Many vaccines are given in early childhood as the immune system of a child is nowhere near fully developed. A number of these will give lifelong protection from a single dose but others need to be boosted some years later. Vaccines are most commonly administered singly but there are some combined vaccines such as the one that gives protection against measles, mumps and rubella (MMR).
Vaccines are made in several different ways. In some vaccines, for example those targeting measles and tuberculosis, live pathogens are treated in the laboratory to make them harmless. They will produce either a mild form of the disease or no disease at all. Some vaccines contain harmless fragments of the pathogen, for example vaccines used against hepatitis B and certain types of meningitis. The tetanus and the diptheria vaccines use the toxins produced by the target diseases. There is a final group of vaccines, for example the injected polio vaccine, which contains the dead pathogen.
They all work in a similar way. Pathogens have proteins on their surface which are termed antigens. These antigens are detected by the white blood cells which then produce antibodies. The antibodies will either engulf and destroy anything with the antigen or render it harmless. But that is only part of the story. In order to protect you from these infections in the future, some of the white blood cells 'memorise' the antigen and the corresponding antibody. Thus, should you become infected at some point in the future, your immune system can start to produce the correct antibodies to eliminate the infection before it gets to the stage where the pathogen can reproduce faster than your white blood cells can destroy it.
Try this quiz and see how well you understand how vaccination can help our immune systems to combat disease.
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