VOICE-OVER: Bacteria and viruses can make you ill.
When you catch a disease, like measles, you build up an immunity to that disease.
This helps prevent you from catching it again.
Vaccines are a way to build up immunity without getting ill first.
A vaccine contains a weakened type or small parts of a virus or bacteria.
Your body responds to the vaccine by making antibodies.
That way, if you are later exposed to the real virus or bacteria...
your body will recognise it and quickly make extra antibodies.
As a result, you’ll not get ill or will be less ill than you would be otherwise.
Sometimes, more than one dose of a vaccine is needed to achieve this.
The viruses or bacteria in a vaccine are either dead or too weak to make you truly ill.
Sometimes, there are side effects after receiving a vaccine...
such as a sore arm or a fever.
These symptoms usually go away after a day or two.
After that, you will be better protected against the disease.