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Vaccines work with our immune system to keep us from getting sick.

Immunity and Vaccines Explained

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<div class="rich-text">Our bodies are bombarded by bacteria and viruses. For those that make their way inside, our immune system is on guard, waiting not only to kill the invaders but also to create memory cells that will help defeat them more quickly the next time they try to attack. Vaccines, which are weakened versions of a disease like polio or measles, rely on the memory of our immune system to combat the real danger if it eventually enters our bodies.
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<div class="rich-text">Vaccines work with our immune system to keep us from getting sick.</div>

Body & Brain

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 Immunity and Vaccines Explained
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 Posted: September 5, 2014


 Immunity is a natural defense system of the human body.


 Imagine millions of immune cells, like white blood cells, all on the look out for specific germs.


 If they spot something dangerous, like flu, they prepare to fight.


 When that flu bug enters your body, the white cells move in on it.


 The immune cells arm themselves and then replicate, creating an army of clones.


 Then, they launch powerful germ-killing agents called antibodies, and they tag the germs for disposal.


 Once the germ is removed, the immune army can disband.


 But they leave behind memory cells.


 Their job is to remember the invader and to sound the alarm if it ever appears again.


 The first time around, it can take at least a week to mount the defense. But next time, the system is prepared.


 The whole process takes barely a day—it’s so fast, we may never have time to feel sick.


 A vaccine pre-arms the immune system by sending in a weakened or dead version of the germ, just enough to be recognized.


 The immune cells mount the defense, and again, you may feel the effect. But because the threat is low, the immune cells quickly disband.


 However, the all-important memory cells have been created.


 The immune system is now prepared for the real germ, but without causing full-scale disease.
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