[Smallpox--past, present and future]

Smallpox has played a notorious role in human history. It has been the cause of millions of deaths throughout the centuries, yet, it was the first infectious disease that was ever eradicated thanks to a worldwide program. Smallpox vaccine, manufactured from the vaccinia virus, was the first vaccine ever produced. Recent bioterrorism events in the USA have brought smallpox back into the limelight, both medically and politically, because of the fear of the return of this horrific disease through the unscrupulous actions of terrorists who might spread variola virus. This article presents the history of smallpox, emphasizing its clinical variants. We also review the treatment of the disease, especially the vaccine--its efficacy and its disadvantages, and the public health measures that must be taken in order to control the disease. In conclusion, we will discuss the possibility of the resurgence of smallpox and global preparedness for such an outbreak.