Keeping Healthy - Antibiotics and Drug Testing

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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. Antibiotics are used to treat bacterial infections. Bacteria can mutate and become resistant to antibiotics. This is one reason why new drugs are constantly being developed.


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 or 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 no longer in 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.


Some common diseases like influenza (flu) and the common cold are caused by viruses. These mutate quickly, and this changes their surface proteins. This makes it almost impossible to develop a permenant vaccine against them. A new flu vaccine has to be developed every year, after the strain has been analysed. There is no vaccine for the common cold because the virus that causes it mutates far too quickly. By the time a vaccine could be developed, the virus would have changed its surface proteins and would no longer be recognised by the antibodies. The government has policies on vaccination which advises which stage in their life people should be vaccinated against different diseases. The policies and advice are updated as and when new scientific information becomes available. 


During an epidemic, an infectious disease such as influenza spreads very quickly. Epidemics can be prevented if a high proportion of the population has been vaccinated. This reduces the number of people who are able to catch the disease and pass it on to others. The more infectious the disease, the higher the proportion of the population that must be vaccinated to prevent the epidemic. 


Antibiotics are substances that kill bacteria or prevent their growth. They do not work against viruses. It is difficult to develop drugs that kill viruses without damaging the body's tissues. 


The first antibiotic, Penicillin, was discovered by Alexander Fleming in 1928. He noticed that some bacteria he had left in a petri dish had been killed by naturally…


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