Smallpox virions (electron microscopy image). Source


Smallpox is the only human infectious disease which was eradicated from planet Earth. The success was the result of a massive worldwide vaccination campaign that finished successfully in the late 1970s of the twentieth century. But USA and Russia kept live samples of the virus. Later this month the WHO will discuss again whether to keep or destroy the samples.
Should We Destroy Our Last Living Samples of the Virus That Causes Smallpox?