What are vaccinations?
When you come into contact with infection, your body’s immune system springs into action by producing special proteins called antibodies. Antibodies help your body recognise and kill the foreign organisms (usually viruses or bacteria) causing the infection.
When your immune system comes across a certain virus or bacteria for the first time, it takes a few days to produce an antibody specifically to deal with that infection. These antibodies and the cells that create them remain in your body. This means that if you come into contact with the same organism again, your body is rapidly able to make large quantities of the antibody that deals with it so that the infection is removed quickly, often before you develop any symptoms.
Vaccination is a way of introducing your body to an organism so it can be ready if you come across it again.
What types of vaccination are there?
Most vaccines contain either part of an organism or whole organisms that have been killed or inactivated. When introduced to your body , these organisms activate your immune system so it produces antibodies without causing the disease.
For a few diseases, the vaccine is in the form of a live (attenuated) virus which is altered so that it activates your immune system but isn't normally strong enough to cause the disease, unless you your immune system is affected by disease or drug treatments. Examples of live vaccines are:
- yellow fever
- measles, mumps and rubella (MMR)
- BCG, which is used to vaccinate against tuberculosis (TB)
- chickenpox and shingles.