Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Preventing a pandemic: Study suggests strategies for containing a flu outbreak

04.08.2005


Containment in a medium-sized Southeast Asian community may be possible, though challenging, if implemented early, researchers say



Though quick to caution about the many things that could go wrong, researchers say that it may be possible to contain a Southeast Asian outbreak of avian influenza in humans, buying precious time for the production of a vaccine.

Using a computer model to simulate an outbreak in a rural Southeast Asian population, the scientists have shown how a combination of strategies, including targeted administration of antivirals, quarantine and prevaccination -- even with a poorly effective vaccine -- could potentially contain an outbreak in Southeast Asia under many circumstances.


The study, by Ira Longini of Emory University and colleagues, will be published online by the journal Science, at the Science Express website, on Thursday, 4 August.

"Our findings indicate that we have reason to be somewhat hopeful. If -- or, more likely, when -- an outbreak occurs in humans, there is a chance of containing it and preventing a pandemic. However, it will require a serious effort, with major planning and coordination, and there is no guarantee of success," said coauthor Elizabeth Halloran of Emory University.

"Early intervention could at least slow the pandemic, helping to reduce morbidity until a well-matched vaccine could be produced," she said.

The danger of avian flu is that the virus could develop into a new strain that could be transmitted among humans. The virus might mutate, or it might jump over to a human already infected with the flu and then mix, or "reassort," with the human flu virus. Because humans would have little or no immune protection against this strain, it could potentially cause a massive pandemic.

"There were three influenza pandemics in the 20th century alone. The threat of another pandemic, related to avian influenza, is real and very serious. Fortunately, as the new study shows, for the first time in human history, we have a chance of stopping the spread of a new influenza strain at the source through good surveillance and aggressive use of public health measures," said Katrina Kelner, Deputy Editor, Life Sciences, at Science.

A rural Southeast Asian population is a likely place for the new strain to emerge, so Longini and his colleagues based their model on the Thai 2000 census and a previous study of the social networks in the Nang Rong District in rural Thailand.

With this information, they simulated a population of 500,000 in which individuals mixed in a variety of settings, including households, household clusters, preschool groups, schools, workplaces, and a hospital. Social settings for casual contacts, such as might take place in markets, shops, and temples, were also included.

Using the model, the researchers analyzed how the disease, starting with a single case, would spread through the population in a variety of different scenarios.

They found that targeted use of antiviral drugs could be effective for containment as long as the intervention occurred within 21 days and the virus’ reproductive number (which represents the average number of people within a population someone with the disease is able to infect) had a relatively moderate value of roughly 1.6.

A process of administering antiviral drugs to the people in the same mixing groups as the infected person, called TAP for "targeted antiviral prophylaxis," could contain the outbreak as long as it reached 80 percent of the people targeted. A related strategy, GTAP, for "geographically targeted antiviral prophylaxis," which targets people within a certain geographic range of the initial case, produced similar results as long as it achieved coverage of 90 percent.

Vaccination before the outbreak, even with a vaccine that is poorly matched to the actual virus strain, increased the effectiveness of TAP and GTAP.

For even higher viral reproductive numbers, household quarantines would also be necessary to contain the virus. A combination of TAP, prevaccination and quarantine could contain strains with a reproductive number around 2.4. A value of 2.4 is relatively contagious, though some other viruses such as measles are substantially higher. In all cases, early intervention would be essential.

The authors note in their study that the current World Health Organization stockpile of antivirals for avian flu could probably be sufficient to help contain a pandemic in a population like the one in the model, if the stockpile were deployed within two to three weeks of detection.

As part of their study, the researchers consulted with Thai ministry of health officials and concluded that public health workers may decide that TAP, rather than GTAP, is the more realistic strategy, given their resources.

This research effort is part of a network called MIDAS (Models for Infectious Disease Agents Study), supported by the National Institute of General Medical Sciences. A related paper from another group of MIDAS researchers is being published simultaneously in the journal Nature.

Ginger Pinholster | EurekAlert!
Further information:
http://www.aaas.org

More articles from Studies and Analyses:

nachricht Real-time feedback helps save energy and water
08.02.2017 | Otto-Friedrich-Universität Bamberg

nachricht The Great Unknown: Risk-Taking Behavior in Adolescents
19.01.2017 | Max-Planck-Institut für Bildungsforschung

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Microhotplates for a smart gas sensor

22.02.2017 | Power and Electrical Engineering

Scientists unlock ability to generate new sensory hair cells

22.02.2017 | Life Sciences

Prediction: More gas-giants will be found orbiting Sun-like stars

22.02.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>