Should the world finally destroy its last remaining samples of variola , one of the deadliest viruses known to man? For many, a better question might be: why is this even a question? Variola causessmallpox , a highly-infectious disease that kills about a third of its victims and wiped out as many as 500 million people in the 20th century. While smallpox was eradicated in 1980 ( thanks, vaccines! ), the virus lives on in just two countries: Russia and the United States, where just-in-case samples are still being stored in high-security laboratories. The World Health Organization has said these stockpiles should be destroyed – but the question of “when” remains less clear. The General Assembly has met six times to settle on a date for burning the stockpiles but the decision has been deferred each time; on Friday, the question will come up once again at the 67 th World Health Assembly , currently underway in Geneva. Why is the virus being kept around at all? The short answer is fear — fear that smallpox could someday return. More