When you are vaccinated, you receive an injection containing a weakened form or small parts of viruses or bacteria. This makes it possible for your body to build up immunity. It allows your body to recognise the real viruses and bacteria, and to make the appropriate antibodies to fight them off. As a result, they will make you less ill, and may keep you from getting any symptoms at all.
How does a vaccination work?
never had before, it can make you ill. Your body first needs to learn how to fight off that virus or bacteria. Being ill is unpleasant, and can sometimes even be dangerous. A vaccination lets you skip the symptoms. You get an injection and build up immunity. Here’s how it works:
- You are injected with a vaccine containing a weakened form or small parts of a virus or bacteria.
- The viruses or bacteria in a vaccine are either dead or very weak. As a result, you do not get ill, but your body learns how to fight off the disease and make antibodies.
- Sometimes there are side effects, such as a sore arm or fever. They usually go away after a day or two.
- If you are exposed to the real viruses or bacteria, your body will recognise them. Your illness will be less serious, and you may not get ill at all.
What does a vaccine contain?
The vaccine information leaflets list all the ingredients. These can be divided into 3 groups:
- Active substances: parts of the virus or bacteria that your body needs to build up immunity to.
- Excipients: substances that improve the efficacy or shelf life of the vaccine, or make the vaccine easier to administer.
- Residues: residues of substances used in the production of the vaccine. Once the vaccine is ready, these residues are removed as much as possible. However, small amounts may still be present.