Helen Thompson explains the debate:
This month the World Health Organization (WHO) will meet to decide whether or not to destroy the last living strains of the variola virus, which causes smallpox. Since the WHO declared the disease eradicated in 1979, the scientific community has debated whether or not to destroy live virus samples, which have been consolidated to laboratories in Russia and at the U. S. Centers for Disease Control and Prevention (CDC) in Atlanta. Small frozen test tubes preserve the surviving strains, and most were collected around the time of eradication, though some date to the early 1930s.
Inger Damon, who leads the poxvirus and rabies branch at the CDC, and her colleagues argue in an editorial in PLoS Pathogens … to save the virus from full extinction. According to Damon, retaining the live samples will allow researchers to delve into unanswered questions about the variola virus and to test better vaccines, diagnostics, and drugs. “There is more work to be done before the international community can be confident that it possesses sufficient protection against any future smallpox threats,” they write.
Alex B. Berezow lists other reasons to keep the virus samples. Among other arguments:
[E]very once in a while, there is a smallpox scare from historical samples. What was thought to be a 135-year-old smallpox scab turned up in a museum in 2011. It ended up not being smallpox (but possibly a related virus known as Vaccinia). Still, the possibility of smallpox viruses surviving in old human tissue samples is a real enough threat. In an e-mail interview with RealClearScience, Dr. Inger Damon, the lead author of the PLoS Pathogens article, wrote, “The virus is highly stable when frozen; periodically the question of viable virus existing in corpses buried in the northern permafrost is posed, but remains unanswered.”