Possible Strategies for Containing a Flu Outbreak

Though quick to caution about the many things that could go wrong, researchers in the 5 August 2005 issue of the journal Science 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.

A rural Southeast Asian population is a likely place for the new flu strain to emerge in humans, so Ira Longini and 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. Depending on the virus’ reproductive number, which represents the average number of people within a population someone with the disease is able to infect, a combination of strategies was required, and in all cases, early intervention was essential.

Kathy Wren

3 August 2005