How can a needle filled with liquid keep you and your family safe from some diseases?
When you get certain diseases, your body generates antibodies to fight the disease and help you get better. In some cases these antibodies stay in your body even after the disease has gone and protect you from getting the same illness again. This is called immunity.
For diseases that have an available vaccine, you don’t have to get sick to develop immunity; you can get the vaccine instead.
Vaccines contain tiny amounts of viruses or bacteria that are dead, weakened, or have purified components that prompt the immune system to produce antibodies that will attack the virus or bacteria to prevent disease.
Some vaccines may not produce sufficient immunity with one dose. This is why some vaccines include a second or third dose, while other vaccines only require one dose.
For some diseases, we need “booster” doses because the protection of the vaccine wears off over time.
However, no vaccine works for 100% of the people who receive it. That’s why a community is best protected by having more people who are immunized,then there is no one who can pass on the disease to others. This is referred to as herd immunity.