The term 'pandemic' is often confused with 'epidemic'.
Some current pandemics are Swine Flu and HIV/AIDS. Some may consider the common cold a pandemic.
Pandemics have been known to vary unpredictably from very mild to devastating. Swine Flu was predicted to be a really bad outbreak, hence the extreme precautions taken, but it turned out to be a harmless cold. Spanish Flu, on the other hand, was not predicted and caused widespread damage, with an estimated 50,000,000 deaths worldwide.
Pandemics are usually mild if precautions are taken, and usually don't do much harm. While the media may make it sound horrible, they often leave out important details, like the infectivity, number of cases, and death RATE. Most cases are never confirmed, either; usually just the severe cases. You could get swine flu and never know.
Pandemic is also a popular online game in which the player attempts to kill off the human species with the perfect disease.