How to handle an outbreak
Researchers provide blueprint for tackling outbreaks in a changing world
By Morgan Sherburne
As the world grows smaller, warmer and wetter, governments need to have an organizational blueprint about how to best respond to infectious disease outbreaks.
Writing in the journal Science, UF biostatistician Ira Longini, Ph.D., and M. Elizabeth Halloran, M.D, D.Sc., of the Fred Hutchinson Cancer Research Center and the University of Washington, outlined how policymakers and health care workers can use epidemiological methods, statistics, mathematics and models of how well vaccination campaigns work to respond to new, unexpected outbreaks.
“Human connectivity is getting more and more complete. Through jet travel, we can move viruses very quickly,” Longini said. “Viruses can get transported out of previously isolated populations in Africa or other parts of the world within days now instead of years.”
Although the paper was written well before the Ebola outbreak in West Africa, the article addresses that kind of situation. Infectious diseases such as Ebola, for which there is not yet a vaccine or effective treatment, will be a challenge, Longini said.
“We really don’t know how to control these diseases. We don’t have vaccines, antivirals, antibacterials or whatever is needed to do what we need to do when we don’t know what the next big pandemic threat will be,” Longini said. “This paper gives a blueprint or roadmap of how to work efficiently in that kind of environment.”
They suggest creating mobile stockpiles of vaccines for diseases that have them, such as cholera. Statistical models based on other outbreaks — such as the 2010 outbreak of cholera in Haiti — can help inform policymakers and show health care professionals how to administer a vaccine campaign in an efficient and cost-effective way. For example, the researchers found when 60 percent of a population is vaccinated, nearly 100 percent of the population is protected against disease transmission.
“Taking indirect effects into account when looking at the cost/benefit of vaccination makes a big difference for developing countries that are needing to use some pretty expensive vaccines right now,” Halloran said.
She said although policymakers want to assess these indirect effects, studies are needed to determine other factors in disease outbreak such as the time of infection, the onset and end of a disease’s infectiousness and how the disease is transmitted through human contact in social settings such as homes, schools and workplaces.
The models the researchers use can be adjusted to fit differences in population size, structure and the movement of people within a certain population. Still, a changing world presents new challenges in responding to disease outbreaks.
“It’s like the old Donald Rumsfeld quote: There are the known knowns, there are the known unknowns and the unknown unknowns,” Longini said.