Now suppose you could make your child safe from some of the most deadly diseases in history....And suppose that at the same time you could also help protect your neighbors' children and other children around the country from the same diseases....And finally, suppose you could actually help to rid the world of some of these diseases that have been crippling and killing children for centuries.
Vaccines are an amazing success story.
Up through the early 1920's, diphtheria was one of the most dreaded childhood diseases in the United States, killing over 10,000 people every year. We started vaccinating children against diphtheria in the 1930's and 40's, and the disease started disappearing. Today it is rare for a doctor even to see a case of diphtheria, much less have a child die from it.
In 1962, the year before measles vaccine was introduced, almost 500,000 cases of measles were reported in the U.S. Ten years after we started vaccinating there were about 32,000 cases, and ten years after that there were fewer than 2,000. In 1998 and 1999, only about 100 measles cases were reported each year.
Until the middle of the 20th Century, smallpox was one of the most devastating diseases the world has ever known. Millions died from it every year. In 1967, the World Health Organization declared war on smallpox with an intensive, worldwide vaccination campaign. Twelve years later, smallpox was wiped out - gone from the Earth forever.
Parents in the 1950's were terrified as polio paralyzed children by the thousands. Then we learned how to prevent polio using the Salk and Sabin vaccines. Now the fight against polio is nearly won, and soon it will join smallpox as nothing but a bad memory.
Before we discuss the 12 routine childhood vaccines and the diseases they can prevent, let's take a brief look at what vaccines are and how they work. Then we will answer some of the questions parents ask about childhood shots.
How Immunity Works
You get sick when your body is invaded by germs. When measles virus enters your body it gives you measles. Whooping cough bacteria cause whooping cough. And so on.
It is the job of your immune system to protect you from these germs. Here's how it works:
Germs enter your body and start to reproduce. Your immune system recognizes these germs as invaders from outside your body and responds by making proteins called antibodies. Antibodies have two jobs. The first is to help destroy the germs that are making you sick. Because the germs have a head start, you will already be sick by the time your immune system has produced enough antibodies to destroy them. But by eliminating the attacking germs, antibodies help you to get well.
Now the antibodies start doing their second job. They remain in your bloodstream, guarding you against future infections. If the same germs ever try to infect you again - even after many years - these antibodies will come to your defense. Only now they can destroy the germs before they have a chance to make you sick. This process is called immunity. It is why most people get diseases like measles or chickenpox only once, even though they might be exposed many times during their lifetime.
This is a very effective system for preventing disease. The only problem is you have to get sick before you develop immunity.
How Vaccines Help
The idea behind vaccination is to give you immunity to a disease before it has a chance to make you sick.
Vaccines are made from the same germs (or parts of them) that cause disease - measles vaccine is made from measles virus, for instance, and Haemophilus influenzae type B (Hib) vaccine is made from parts of the Hib bacteria. But the germs in vaccines are either killed or weakened so they won't make you sick.
Then the vaccines containing these weakened or killed germs are introduced into your body, usually by injection. Your immune system reacts to the vaccine the same as it would if it were being invaded by the disease - by making antibodies. The antibodies destroy the vaccine germs just as they would the disease germs. Then they stay in your body, giving you immunity. If you are ever exposed to the real disease, the antibodies will be there to protect you.
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