Getting shots is important. A little pain from a shot will save you from a lot of pain if you get sick. Getting vaccinated will protect you from diseases, even if you are exposed to the germs that cause the disease.
The word vaccination comes from a medical name for cowpox, vaccinia, which comes from the Latin word vacca, which means cow. Vaccines are a way to stay immune from diseases. The antibodies in the vaccine protect your body. Most vaccines are shots. Few are a squirt of liquid into the mouth or a nasal spray.
The first helpful vaccine was created in 1796 by Edward Jenner. First, Dr. Jenner injected an eight year old boy with the liquid, pus, or scabs from a patient of cow pox. The boy suffered from mild symptoms. Seven weeks later, Jenner vaccinated him with smallpox liquid. The boy didn't get smallpox so the vaccine had worked.
Most vaccinations are based on the disease they are supposed to protect against. They may contain the actual bacteria or virus in the disease, but they aren't very strong. The weakened germs cannot multiply. But the person who gets the live vaccine may suffer from the disease.
Killed vaccines have dead bacteria or viruses in them, but the vaccine can still create antibodies. These vaccines are safer than live vaccines. Yet one other type of vaccine is made to protect from the poisons germs can produce. These vaccines contain the poisons that are chemically changed, called toxoids.
Vaccines are almost always safe. You may have mild reactions, like soreness. Did you know that someday you may be able to get a vaccine by eating a banana?
The more people who are vaccinated in your community, the safer you are. Let's say that only 40% of the people in your town are vaccinated against a certain disease. That gives germs a better chance of making a home in your body. But if 90% of the people in your town are vaccinated against the disease, the you have less chance of getting it from somebody else. This is called herd immunity. Sometimes if you travel to a part of the world that has many people with a disease, you could catch it and bring it back to wherever you live.
There are two main types of germs that cause diseases; bacteria and viruses. Bacteria need nourishment from their environment to live. That environment could be in a person's body. As soon as the bacterium enters your body, it multiplies into two bacteria every 20-30 minutes. After a few hours, you could have millions of bacteria in you body. The bacteria lets out poison that damages or kills body cells. That's when you start to feel sick.
Viruses don't give off poisons but they can kill body cells when they multiply. A virus invades a body cell, and then that cell turns into something that can create viruses. When the cell is filled with viruses, the viruses spill out. Then these viruses invade other cells and the process repeats itself. When this happens, you start to feel sick.
Many different diseases are contagious. With some you may breathe in small moist droplets that an infected person sneezed or coughed out.
There are other ways you can get sick, too. If you have an open cut, bacteria that lives in dirt could get in through the cut. Sometimes swimming water can carry bacteria that can get in through your nose, mouth, or ears.
Since all these things can happen to you, your body has a built-in defense system called your immune system. If germs try to enter through your nose, they could get caught in the hairs inside your nostrils. But some may get past these hairs and get caught in your noses mucus. When you sniffle, the mucus will take the trapped germs to the back of your throat. Then this gets swallowed into your stomach and the acid destroys the germs.
Your immune system can also stop bacteria and viruses. When the germs damage or invade a cell, the cell can actually call for help. They don't use the telephone, instead they send out chemicals that tell white blood cells to come and save them. These blobs travel through your blood. They destroy the germs and sometimes eat them.
Killer T cells can detect viruses. They destroy infected cells along with all the germs they contain.
Because of your immune system, some diseases like chickenpox you can only get once. The first time the disease enters your body, it learns what that germ is like so the second time it tries to enter, your body knows exactly what the germ is and can kill it right away.
Vaccinations Children May Receive
Birth to Two months-Hepatitis B
Dr. Silverstein, Alvin, Silverstein, Virginia, Silverstein Nunn, Laura. Vaccinations. Scholastic Inc. New York, NY. 2002.
Images of syringe, ear, and baby from "Microsoft Office Online" <http://office.microsoft.com/clipart/default.aspx?cag=1> Images free for non-profit and personal use. (October-February, 2003-2004).
Bernstein, Joanne E. and Paul Cohen. Dizzy Doctor Riddles. Niles, Illinois: Albert Whitman & Company. 1989.