Vaccination
After the provision of safe food, water and sanitation, the most important public health measure in the world is vaccination.
Many infectious diseases, previously responsible for millions of deaths, are being controlled through vaccination. Some, such as smallpox, have now disappeared from the Earth.
The purpose of vaccination is to produce immunity.
Immunity means the presence in a person's body of substances known as antibodies. These substances attack viruses and bacteria, stopping them multiplying, thus preventing particular infections developing.
Antibodies are specific to each individual disease. Having antibodies to measles does not protect you from catching mumps or chicken-pox, etc.
Immunisation means the creation of these antibodies in a particular individual. This can happen in one of 2 ways.
- Active immunisation: this happens either by having an attack of the infection or through vaccination with a dose of the responsible virus or bacteria which has been killed or inactivated. Active immunisation is usually long lasting. It may take some time to fully develop and often needs ‘boosting’.
- Passive immunisation: this is a way of giving immediate immunity by injecting already existing antibodies (from someone else) into a person who has just been, or may shortly be, exposed to a particular infection. Passive immunity is immediately effective, but doesn't last for long.
The creation of immunity through vaccination is usually started in the very early months of a child's life. In most countries children are immunised against tetanus, whooping cough, diphtheria, haemophilus influenzae B (HiB), polio, measles, mumps and rubella (german measles). Many authorities now also advocate hepatitis B immunisation for all children.
As well as being of vital importance in childhood, vaccination is also essential for adults. Adults should remain immune to the following infections.
- Tetanus: booster vaccination needed every 10 years.
- Diphtheria: given in combination with tetanus.
- Polio: still present in less developed parts of the world.
- Measles, mumps and rubella (German measles): childhood infection or vaccination usually gives life-long immunity. But these infections can cause serious illness in adults who didn't have them, or were not vaccinated, as a child. It is very important that pregnant women are immune to rubella.
- Hepatitis A: an infection caused by eating/drinking unclean food or water. Active immunity is now available through vaccination. Passive immunity possible for short term protection for those about to travel in ‘third-world’ conditions.
- Hepatitis B: a serious illness which can have permanent effects. Spread by contact with body fluids (e.g. blood, saliva, semen) of an infected person. Active immunity is possible with a series of 3 injections and five-yearly boosters. Important for healthcare workers.
- Influenza: a yearly vaccination for those at risk of complications.
- Pneumonia: vaccination every 5 years for elderly and those at risk.
- Tuberculosis (TB): still quite common in some countries and those exposed should be immune.
Immunisation is simple, safe and readily available. If you have any doubts about your own immunity, or if you travel overseas frequently, see your doctor and check that you are adequately protected.
Last Reviewed: 08 May 2002
