Biology - Vaccination

What is vaccination?

Vaccination provides immunity to specific diseases. A person who had been vaccinated has artificial immunity. This is created by deliberate exposure to antigenic material that has been rendered harmless. The immune system treats the antigenic material, as a real disease. As a result, the immune system manufactures antibodies and memory cells. The memory cells provide the long-term immunity.

The antigenic material used in vaccinations can take a variety of forms:

·         Whole, live microorganisms – usually ones that are not as harmful as those that cause the real disease. But they must have similar antigens so that the antibodies produced will be effective against the real pathogen (e.g. the smallpox vaccine).

·         A harmless or attenuated version of the pathogenic organism (e.g. measles and TB vaccines)

·         A dead pathogen (e.g. typhoid and cholera vaccines).

·         A preparation of the antigens from a pathogen (e.g. hepatitis B vaccine).

·         Some harmless toxin (called a toxoid) (e.g. tetanus vaccine).

Vaccination can be achieved by injection, or the vaccine can be taken orally.

Herd Vaccination: is using a vaccine to provide immunity to all or almost all of the population at risk. Once enough people are immune, the disease can no longer spread. In order to be effective, it is essential to vaccinate almost all the population.

In the UK there is a vaccination programme to immune young children against the following diseases: TB, diphtheria, tetanus, whooping cough, polio, meningitis, measles, mumps and rubella.

Ring Vaccination: is used when a new case of a disease is reported. Ring vaccination involves vaccinating all the people in the immediate vicinity of the new case(s). This may mean vaccinating the people in the surrounding houses, or even the whole village or town. Ring vaccination is used in many parts of the world…