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DEFENCE AGAINST DISEASE

VACCINES AND VACCINATION

Vaccination is a prophylactic treatment used to fight infections that the body may encounter in the future. Some however (e.g. rabies) are used as post infection vaccination.

The principle is to stimulate the immune system by exposing it to harmless antigens.

The immune response leaves memory cells so that when the real infection by a pathogen takes place the immune response is rapid and the body resists.

A typical immune response to vaccination

 

Vaccines come in several forms:

  • Purified antigens from the pathogen
  • Dead pathogens or parts of pathogens
  • Live but attenuated (harmless) pathogens

Memory is not perfect and so booster vaccination may be necessary.

Because of complications with certain vaccines the types of vaccination given is usually limited to those diseases that are endemic to the region.

The benefits and dangers of vaccination
 

Benefits
  • Vaccination has helped to cut infantile death rates in many parts of the world
  • Some diseases (e.g. small pox) have been eliminated totally. Others (e.g. polio) are programmed for elimination.
  • Vaccination has helped to contain the spread of a number of diseases.
  • Vaccines are a cheap form of prophylactic treatment.

 

Dangers
  • Live vaccines containing attenuated (harmless viruses may "jump" to another virus in the system (e.g. attenuate live polio virus given to a person contaminated with HIV may develop polio). Even close members of the family may be affected this way.
  • Vaccines may lead to allergic responses or auto immune diseases e.g. Crohn’s disease (inflammation of the digestive system) and MMR vaccination
  • Vaccines have been associated with clinical conditions (e.g. MMR and autism). MMR is a triple vaccine for Mumps, Measles and Rubella (German measles). It usually contains a small amount of mercury. Some argue that this mercury acts as a neurotoxin.
  • Multiple vaccinations received by soldiers fighting in the Gulf War 1991 are associated with a number of health problems (The Gulf War Syndrome):
Chronic Fatigue
Skin rashes and unusual hair loss)
Headache
Muscle pain
Neurological signs or symptoms (nervous system disorders which could manifest themselves in numbness in one's arm, for instance)
Neuropsychological signs or symptoms (including memory loss)
Signs or symptoms involving upper or lower respiratory system
Sleep disturbances
Gastrointestinal signs or symptoms (including recurrent diarrhoea and constipation)
Cardiovascular signs or symptoms
Menstrual disorders

From: Internet Reference

Vaccines a victim of their own success?

As infectious diseases become rarer in a population the attention of parents tends to be focussed on the problems with vaccines. They become reluctant to vaccinate their children or they become complacent about the risk of infection.

When measles vaccination rates went down in 1990 in the United States, there was an outbreak of 28 000 cases of measles, and 30 children died.

© Paul Billiet 2004