Updated February 21, 2017 | Factmonster Staff
Source: The U.S. Food and Drug Administration (FDA)

Why do we need vaccines?

Vaccines protect us against deadly diseases like measles, mumps and whooping cough.

How do vaccines work?

When you receive a vaccine it helps your body create antibodies. Antibodies are your body's defensive cells that fight off any foreign substance (germs). Sometimes your body can create antibodies on its own. But the diseases you get vaccines for are very dangerous. Most people get very sick and some die before enough antibodies are produced.

Here's more about the diseases we get vaccinated against:

Hib Vaccine

This vaccine protects us from the Haemophilus Influenza type b bacteria.

This bacteria causes meningitis, (an inflammation of the cover that surrounds the brain) and may cause brain damage. Also this bacteria can infect the blood, joints, bones, muscles, throat and the cover surrounding the heart. This is especially dangerous for babies.

DTP Vaccine

The D in DTP stands for Diphtheria.

Diphtheria is an infection that attacks the throat, mouth and nose. This is a very contagious disease (easy to get), but rare ever since the vaccine was created.

Diphtheria can form a gray web that may completely cover the windpipe and cause someone to stop breathing. Also, if this disease is not treated right away it could cause pneumonia, heart failure or paralysis.

The T in DTP stands for Tetanus.

Tetanus is an infection caused by a bacteria found in dirt, gravel and rusty metal. It usually enters the body through a cut.

Tetanus bacteria causes the muscles to spasm (move suddenly). If tetanus attacks the jaw muscles it causes lockjaw, the inability to open and close your mouth. Tetanus can also cause the breathing muscles to spasm. That can be deadly.

The P in DTP stands for Pertussis.

Pertussis, also called Whooping Cough, is a bacteria that clogs the lungs with mucus (a thick, slimy substance). This can cause a severe cough that sounds like a "whoop." The cough can last for 2 months and allows for other bacteria such as pneumonia and bronchitis to attack the body.

Polio Vaccine

Polio can paralyze (can't move) the legs and chest making walking and breathing difficult or impossible.

The first symptoms of polio are fever, sore throat, headache and a stiff neck. Polio has become very rare in most of the world since the vaccine became available.

MMR Vaccine

The first M in MMR stands for Measles.

Measles is a highly contagious (easy to get) disease that causes a high fever, cough, and a spotty rash all over. It may also cause ear infections and pneumonia.

The second M in MMR stands for Mumps.

Mumps causes painful swollen salivary glands which are under the jaw, as well as a fever and a headache. Mumps also may cause a serious problem called meningitis or hearing loss.

The R in MMR stands for Rubella.

Rubella is also called German Measles. It is most dangerous for women who are pregnant. Rubella can cause a mother to have a miscarriage (lose the baby) or deliver a baby with heart disease, blindness, hearing loss or learning problems. Rubella is a mild disease in kids.

Hepatitis B Vaccine

Hepatitis B causes extreme tiredness and jaundice (all the white parts on your body, like your eyes, teeth and nails, turn yellow). It may cause the liver to stop working.

Chicken Pox Vaccine

Chicken pox is a virus. It causes an itchy rash and a fever. You can catch it from someone who already has it if you touch an open blister on that person's skin or if that person sneezes or coughs around you. Not everyone gets the vaccine, so lots of kids still get chicken pox.