The discovery of several vials of smallpox virus at the back of a cold storage room at the National Institutes of Health have not only embarrassed scientists and fed global headlines, but it's also dredged up memories of humankind's one and only complete triumph over a deadly disease.
Dr. D. A. Henderson, who helped lead the effort to eradicate smallpox in the 1970s, says he's not worried that incidents like this one could ever bring it back. But it is a reminder that victory over disease is, at best, tenuous.
Earlier this week, the CDC reported that workers on the NIH campus had found vials of smallpox in a storage room in a Food and Drug Administration office. They were marked “variola,” the scientific name for smallpox, and dated 1954.
“I thought, ‘Holy Toledo,’” said Henderson, professor emeritus at Johns Hopkins School of Public Health.
U.S. Centers for Disease Control and Prevention officials announced Friday that the two vials they tested have viable virus - not quite alive, because viruses need a host organism, but able to grow when put into a nourishing lab culture. "This is growing in our approved smallpox containment laboratory, a BSL-4 facility," CDC Director Dr. Tom Frieden said Friday. Biosafety level 4 (BSL-4) labs have the very highest level of security to ensure that the virus cannot escape the room and cannot infect the people working with it.
So while the smallpox does not appear to be a threat to anybody, it still must be destroyed, and now staffers will be scouring government facilities to make sure there isn't any more sitting at the back of some freezer. Here are some things to know about smallpox:
It’s gone — almost.
The ancient scourge is the first and only human disease to have been eradicated, in 1980, after a sustained vaccination campaign. All the stocks were supposed to have been destroyed under a global agreement, with the exception of two stores, one at the CDC and one in Russia. The World Health Organization has been gently pressing the U.S. and Russia to agree to destroy their samples but earlier this year quietly shelved another discussion of the issue.
The samples stored at NIH were packed away long before this debate, however, says Frieden. "The problem was not in the creation of the materials but in the inventory control which allowed them to remain unsecured for decades," Frieden told reporters Friday. "They should have been destroyed decades ago, and once we complete the work here, we will destroy them."
It was really, really bad.
Smallpox killed as many as 500 million people in the 20th century alone. It’s highly infectious, with a death rate of 30 percent. The virus can survive for a while on surfaces — the early settlers of what became the United States notoriously rubbed the liquid oozing from smallpox pustules onto blankets that they then traded to native Indian tribes, causing epidemics that wiped out most of the population in places.
It still scares people.
A former Soviet bioweapons expert named Ken Alibek, who now lives in the United States, says his former employers made smallpox into a weapon, putting it into bombs to be exploded in the U.S. in the case of total war. Iraq was also suspected of making smallpox into a weapon, although evidence of this was never found. Many bioterrorism experts say it’s important to keep smallpox and smallpox vaccine on hand in case it ever is used as a weapon — or in case of a lab accident. The United States freshly vaccinated many servicemen and women in 2003 in case of an attack and has 220 million doses of vaccine in deep-freeze storage.
People tried to vaccinate against it for centuries.
The first real vaccine was one against smallpox, made by Edward Jenner in 1796 from a related virus, cowpox. Current vaccines are made from another related virus called vaccinia. But hundreds of years before that, people knew they could use scabs taken from smallpox lesions to deliberately infect people and that people sickened in this way often didn’t even get sick, or if they did, the mortality rate was 1 to 2 percent compared to the usual 30 percent.
People were still using this method, called variolation, in Afghanistan into the 1970s, says Henderson. “What they do is take out a couple of scabs, put them in a mixing bowl and sort of grind it up with something like milk, to make an emulsion, and then they could make a couple of cuts on the arm and rub it in,” he said. “The only trouble was, and why we tried to stop the practice, is the individuals who were variolated, they were as contagious as any smallpox patient."
Those newly discovered vials were unlikely to have been a threat.
Henderson's efforts to stop variolation gave him deep understanding of the virus and give him confidence that the old NIH samples, even if alive, are unlikely to be very potent. The people who were using old scabs to variolate others kept stocks of smallpox scabs. “We did studies of smallpox scabs to see how long you can keep them,” Henderson said. “Even when kept in the cold mountains of Afghanistan, they wouldn’t (stay infectious) for more than eight or nine months over winter."
Infectious disease experts expressed astonishment Friday night that the smallpox discovered at NIH had remained viable for 60 years.
Human foibles stalled eradication efforts. As modern medicine and vaccination efforts drove smallpox into increasingly remote zones, it was human error and not diabolical viral behavior that foiled efforts time and again. In Afghanistan, the age-old practice of variolation interefered with eradication. "You could track the variolators down the trail," Henderson remembered. They would leave people infected in their wake. And the last U.S. outbreak, in 1947, was blamed on a complacent population that had stopped getting vaccinated because so few people had ever seen smallpox. A few travelers imported the virus and two people died in the epidemic that followed. More than six million were vaccinated in the panic that followed.
There is still a vaccine. The vaccine used to wipe out smallpox wasn’t a very safe one, causing side-effects that killed about one in a million people vaccinated. Newer vaccines are safer, although they also contain a live virus — not smallpox but vaccinia — that can sicken vulnerable people. If there was any risk of a smallpox outbreak, for instance if a lab worker somehow got infected, experts are confident spread could be contained by what's called ring vaccination-- tracking down and vaccinating anyone who conceivably could have been in contact with the infected person.