I get my flu shot each fall without really thinking about the miracle it represents. In an age where our health worries focus on osteoporosis, impotence and incontinence, it's easy to forget what horrors our routine vaccinations have removed from our consciousness.

When I was very young, the U.S. was in the midst of a polio panic. In 1952, 58,000 cases were reported, leaving thousands dead and tens of thousands to suffer with some degree of paralysis. Thanks to the Salk vaccine, released in 1955, by 1961 this number had dropped to 161, and children were once again free to go swimming and play together.

Back then, we all shared measles, which I thought was a fairly innocuous rite of passage. Did you know that, over the past 150 years, an estimated 200 million people have been killed by the measles? Thanks to a vaccine, it has all but been eradicated in the U.S.

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When was the last time you heard of a case of diphtheria? In the 1920s, over 100,000 cases were reported annually in the U.S., killing 13-15,000 each year. Again, a vaccine has made it a thing of the past, here.

How about the white plague? This nickname for tuberculosis captured the dread the public felt for a disease that was easily spread , killing by destroying a patient's ability to breath. A vaccine developed early in the 20th century dramatically reduced infant deaths from TB.

Yet the World Health Organization estimates that today 2 billion people have been exposed to TB, and each year eight million fall sick with the disease, of which 2 million die. It is the most common infectious killer of women of child-bearing age and of AIDS sufferers. New, more effective vaccines are being developed, and none too soon.

Perhaps not every vaccine available is without its downside, but, in general, I can't think of any 20th century discovery that has done more to stem human misery than the vaccine. So when you get your flu shot, take a moment to consider your life without vaccines. If you'd even have one.