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Science

Keeping healthy

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Immunisation - higher

People can be immunised against a pathogen through vaccination. Different vaccines are needed for different pathogens [pathogens: microorganisms that cause disease ].

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

  • live pathogens treated to make them harmless
  • harmless fragments of the pathogen
  • toxins [toxins: a type of natural poison produced by an organism, often as a form of protection ] produced by pathogens
  • dead pathogens

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

Because the vaccine contains only a weakened or harmless version of a pathogen, the vaccinated person is not in danger of developing disease - although some people may suffer a mild reaction. If the person does get infected by the pathogen later, the required lymphocytes are able to reproduce rapidly and destroy it.

Antibiotic resistance

Over time, bacteria can become resistant to certain antibiotics. MRSA is methicillin-resistant Staphylococcus aureus. It is very dangerous because it is resistant to most antibiotics. To slow down or stop the development of other strains of resistant bacteria, we should:

  • avoid the unnecessary use of antibiotics
  • always complete the full course

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