A woman holds her baby as she is given a shot during an immunization program at the Adora New Clinic July 31, 2004, in Baghdad, Iraq. Programs to immunize children against fatal childhood diseases were suspended during the war but have been revived. See more modern medicine pictures.
Joe Raedle/Getty Images
Vaccines have changed the face of disease around the world. The World Health Organization (WHO) estimates that vaccines prevented 2 million childhood deaths in 2003, and the numbers continue to rise as vaccination supplies become available in developing countries. Vaccines often have a bad reputation because they can cause side effects, but even when someone does experience side effects, they're mostly mild -- serious reactions happen, but they're rare.
Most vaccines are given to children under the age of five, when they haven't yet had time to develop a strong immune system and are most vulnerable to infections. When we're vaccinated, our bodies react by creating antibodies against the particular virus or bacteria. If we're exposed to it later in life, those antibodies help us fight off the potential infection. We're not actually killing bacteria or viruses, we're taking ourselves out of play. Without vaccinations, we'd again be susceptible to a number of diseases. Here, we'll look at 10 vaccines that changed the world. Let's begin with the flu shot.
