In the computer model, simulated treatments included the targeted use of antiviral medications (which typically slow the disease's spread), quarantine, and pre-vaccination in selected areasdespite the use of relatively inefficient vaccines.
While results varied, they often showed a reasonably high probability that an outbreak could be contained in a variety of scenarios.
Early intervention was key to each successful outcome.
"What we show is that the ability to implement something fairly quickly in a couple of weeks is important, otherwise [the virus] will likely get out," Halloran said.
The study will be reported in Friday's issue of the journal Science.
Buying Time at the Outbreak's Source
Anthony Fauci directs the National Institute of Allergy and Infectious Diseases at the National Institutes of Health in Bethesda, Maryland. He called the model valuable but noted that "any model is only as good as the assumptions put into that model, and these really are only assumptions."
Still, such models can give experts "some specifics about options available that might be able to contain an epidemic early on, " he said.
Fauci said that the new study confirms that even a limited supply of antiviral drugs can help slow the spread of a virus in a particular region. "The same is true with a partially effective vaccine. That can also slow the spread of a disease."
Harder to diagnose is how outbreaks behave in the face of unknown variables such as the makeup and behavior of the virus, as well as human factors, like the ability to recognize and monitor a developing outbreak.
"If you find [these things] out a couple of months after it's started, you're in big trouble, and the types of measures recommended in the model won't help," Fauci said.
"This underscores the need for surveillance and the need for transparencynamely countries letting people know immediately when they have a situation, because the longer you wait, the less effective the intervention becomes," he said.
To make matters worse, in cases where the disease is very contagious from the onset, treatment has very little effect.
The large number of unknowns leaves some experts skeptical that models can help contain virus outbreaks.
"In this case there are any number of issues," said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota in Minneapolis.
"It's not just having in place the ability to move antiviral drugs to an areathough that is a concernbut the entire system. What kind of surveillance do you have to spot the appearance of an illness? How quickly can you do lab tests to find out what's actually happening?" Osterholm said.
"What kind of system do you have in place to really control population movement [for quarantine]?" he continued. "Look at the model from the early days of SARS. One individual left a given area and suddenly overnight you had [the illness] in multiple countries."
Osterholm has been a vocal proponent of coordinated international efforts to prepare for a potentially devastating pandemic.
"I worry that these kinds of studies leave policymakers with the sense that there is something meaningful we can do at the local level to stop this, which may prevent them from addressing the global issues pertaining to a pandemic," he said. "And we can't for one minute ease the pressure on them to do that"
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