The revelation that 6 vials of smallpox--the only human disease mankind has eradicated--were found in an FDA storage room at the NIH will likely grab headlines and spark concerns of a smallpox outbreak. However, I do not anticipate this event will amount to much.
As is widely known, smallpox was eradicated from the planet in the 1970s and vaccination soon stopped. This cessation of vaccination has rendered most of the population susceptible to smallpox...if it were to return through an accidental lab release or deliberate attack--a major concern for those in the fields of biosecurity and bioterrorism.
In the post-eradication era, the known stocks of the virus are kept in secure locations at the CDC in Atlanta and the Vector Institute in Novosibirsk (Russia). The retention of the virus has sparked continual debate at the World Health Assembly regarding whether these stocks should be destroyed or retained.
Further testing remains to be performed to determine whether what was found at the NIH was viable virus and the fact that it was freeze-dried may have preserved infectivity. Indeed, the vials have tested positive for smallpox DNA and the next step will be to assess whether the virus can be cultivated in culture. Nevertheless, though these vials do not pose any risk to the general public, the fact that forgotten stores of the deadly virus exist in the US makes it all the more possible that such remnants exist in other parts of the world.