In Disease Outbreak Management, Flexibility Can Save Lives and Money

A new approach for responding to and managing disease outbreaks is being proposed by a team of epidemiologists led by two Penn State University researchers. The team's flexible approach could save many lives and millions of dollars.

The approach, called "adaptive management," allows decision-makers to use knowledge they gain during an outbreak to update ongoing interventions with the goal of containing outbreaks more quickly and efficiently. Current efforts to prevent or stem such outbreaks may fall short because of uncertainty and limited information about the real-time dynamics of the specific disease outbreak. The researchers have written a scientific paper on this adaptive management approach that will be published on 21 October in the open-access journal PLOS Biology.

"Responders often have incomplete information during a disease outbreak," said Katriona Shea, professor of biology at Penn State and a leader of the research team. "Everyone is trying to make rapid decisions, but we don't have reliable information to make the best decisions. Even if we have information about a previous outbreak, no two outbreaks are identical. Adaptive management involves planning to learn as you act for the most effective, efficient response."

In their PLOS Biology paper, the authors present two scenarios in which adaptive management likely would improve outcomes. One of Shea's co-authors is Matthew Ferrari, a leader of the research team and an assistant professor of biology and statistics at Penn State, who consults with organizations such as the Centers for Disease Control, the World Health Organization, and Doctors Without Borders on disease-outbreak prevention and response, cited measles vaccination as one example.

Microscopic image of the measles virus. Credit: Shmuel Rozenblatt, Tel-Aviv University

In measles outbreaks, Ferrari explained, responders need to make decisions and to act quickly based on the information available. An outbreak contained to young children would call for a fast and nimble response, moving from town to town very quickly and vaccinating only young children. Conversely, an outbreak affecting a broader age range requires a slower, broader, more methodical response. "There are tradeoffs to taking the wrong approach," Ferrari said. "If you did the fast, nimble child-vaccination response but the outbreak had a broader risk, you would miss a lot of people. If you did the slower, broader, more-methodical response, you'd protect lots of people but the response may not be fast enough."

Organizations such as Doctors Without Borders work quickly to contain outbreaks as well as to prevent further spread. "Preparing, in advance, to include monitoring and evaluation with an eye toward changing management actions in light of changing conditions on the ground is the key to adaptive management. We've shown that a plan to manage adaptively can change the recommended actions on day one because, for example, you only need to manage for the worst-case scenario if it arises," Ferrari said.

The second example the researchers cite is an outbreak of foot-and-mouth disease (FMD) in the United Kingdom in 2001. During that outbreak, almost 600,000 cattle and 4 million sheep were either infected or culled in an effort to prevent further spread of the disease. "Culling decisions during the outbreak were contentious as there was so much uncertainty about the spatial scale of transmission," Shea said. "Many farmers felt that they were being penalized for being in the vicinity of infected farms when they believed that they were not at risk."

Cows, a species susceptible to the contagious foot-and-mouth disease. Credit: Alec Brown

Adaptive management in the case of foot-and-mouth disease initially would employ a less-severe approach that would reduce the number of cattle culled and rely on real-time updates to modify responses -- more-severe culling would be recommended only if justified by the spread of the outbreak. According to Shea, if foot-and-mouth disease were to break out in the United States -- a very real risk -- adaptive-management measures could result in significant savings in terms of reduced livestock losses. "The United States does a huge trade in beef, and the second we are infected all that international trade would shut down," Shea said. "Foot-and-mouth disease is highly infectious and would have to be contained quickly. Adaptive management would incorporate a plan to change intervention efforts appropriately as events unfold."

Historically, Ferrari said, "the argument has been for a very static policy because it's clear and easy to implement. We recognize that a more nuanced, context-specific approach could be better. We need to put the possibility of changing midstream into our toolbox, integrating scientific discovery with policymaking to improve intervention efforts."

The research was funded by the U.S. National Institutes of Health EEID award 1 R01 GM105247-01, the U.K. Biotechnology and Biological Sciences Research Council, the RAPIDD Program of the Science and Technology Directorate of the U.S. Department of Homeland Security, and the Bill and Melinda Gates Foundation.

CONTACTS

Katriona Shea: kus3@psu.edu, (+1) 814 321 4809

Matthew Ferrari: mferrari@psu.edu, (+1) 814-865-6080

Barbara Kennedy (PIO): science@psu.edu, 814 863 4682