By Bill Black, M.D., Ph.D.

I recently took my two teenagers to their doctor to update their immunizations. For a few seconds of pain and a day or two of sore arms, they are now protected against a host of scourges, including meningitis, tetanus, diphtheria, whooping cough, hepatitis and cervical cancer. Vaccines are one of the most effective ways to protect ourselves, our children and our communities from illnesses that once wreaked havoc on humankind.

Here in North America, the germs or microbes that cause disease are mostly bacteria or viruses. Vaccines are extracts of these microbes. By introducing these extracts into our bodies as vaccines, we stimulate our immune system to produce antibodies—protein molecules that bind to and inactivate or destroy the microbe. We also induce a type of memory in our immune system, so that if we encounter that microbe again, our immune systems are primed to rapidly crank up production of those antibodies and eradicate the microbe before it can gain a toehold in our bodies and produce disease.

History of Vaccines

Vaccines have a fascinating history that started with the simple observation in 18th century England that milkmaids were less likely to suffer the death and debilitation of smallpox because many of them had been exposed to cowpox. It was discovered that exposure to cowpox created resistance to smallpox, whether the cowpox had been contracted naturally or artificially by scratching the skin with material from an individual infected with cowpox. The word vaccine comes from "vacca," the Latin word for cow.

There have been some amazing vaccine victories over disease throughout the years. Three hundred years ago smallpox was a devastating disease in Europe, killing one out of seven children in Russia and one out of 10 children in Sweden and France, often leaving survivors scarred or blind. In 1967 the World Health Organization decided to rid the world of smallpox through worldwide universal vaccination, a goal that was accomplished within 10 years. Polio once crippled 20,000 children annually in the United States. The polio vaccine was introduced in the mid-1950s, and today the disease has been virtually eradicated from the Western Hemisphere.

There have also been some troubling backslides. Whooping cough once attacked 200,000 children annually in the United States, killing up to 10,000 each year. After the introduction of the whooping cough vaccine in the 1940s, the number of U.S. cases dipped to a low of about 1,000 in the 1970s. Recently, there has been an increase in the incidence of the disease, and many experts believe this may in part be due to misinformation about the vaccine that scared parents away from getting their children immunized.

Vaccines: A Valuable Tool

We now have vaccines in the United States to prevent about 24 diseases. Some are routinely used, such as the tetanus, whooping cough, flu, measles, mumps and meningitis vaccines. Some are used only for international travel, such as the typhoid or yellow fever vaccines. Some are specialized for seniors or individuals with certain health conditions, such as the pneumonia or shingles vaccines. However they are used, vaccines provide an invaluable tool in our medical armamentarium against the microbes that cause disease.

To see what vaccines are right for you and your child, take the "What vaccines do YOU need?" quiz.

Dr. Black is an internal medicine physician at the PAMF's Redwood City Center.