In 1952 Jonas Salk developed the polio vaccine. The vaccine has been so successful that what was once a common and crippling disease is now nearly eradicated in the U.S.

Vaccines consist of mild doses of disease-causing bacteria or virus that trigger the creation of antibodies that fight infection. In addition to the polio vaccine, many other vaccines have been used to virtually wipe out diseases such as smallpox, measles, and many others. It's standard procedure in most doctors' offices to immunize infants.

But some parents are wary of immunization. A small but vocal minority argues that vaccinations can harm as much as they help. A typical argument may go like this: according to statistics, the chance of a serious reaction to a smallpox vaccine is 1 in 5000. But the chance of catching smallpox in the first place is one in one million. So, why risk a reaction to the vaccine when odds are you won't get the disease in the first place?

The pro-vaccine majority has a ready answer: the odds are so far against coming down with smallpox and other diseases because the majority of the population has been immunized against them. If more people begin to refuse vaccination, the chances of contracting those diseases will almost certainly increase. As for claims that immunization can cause autism and even sudden infant death syndrome, the mainstream medical community has not taken these arguments seriously given their lack of objective evidence.

To immunize or not? The choice is yours, but chances are your doctor will tell you it's a pretty safe bet.