Tuesday, March 11, 2008

Delaying A Pandemic

 

 

# 1774

 

 

 

The idea is simple, although its implementation may prove quite difficult.   If a pandemic erupts, deny the virus access to susceptible hosts and you slow the pandemic down to a crawl.   

 

If you can do so long enough, and efficiently enough, you can conceivably delay a pandemic's worst effects until after a vaccine becomes available. 

 

 

The following study appears in the March 10,2008 edition of PNAS (Proceedings of the National Academy of Science).

 

Modeling targeted layered containment of an influenza pandemic in the United States  

 M. Elizabeth Halloran*,{dagger},{ddagger}, Neil M. Ferguson§, Stephen Eubank, Ira M. Longini, Jr.*,{dagger}, Derek A. T. Cummings§, Bryan Lewis, Shufu Xu{dagger}, Christophe Fraser§, Anil Vullikanti, Timothy C. Germann||, Diane Wagener**, Richard Beckman, Kai Kadau||, Chris Barrett, Catherine A. Macken||, Donald S. Burke{dagger}{dagger}, and Philip Cooley**

 

 

 

Abstract  (reparagraphed for readability)

 

Planning a response to an outbreak of a pandemic strain of influenza is a high public health priority. Three research groups using different individual-based, stochastic simulation models have examined the consequences of intervention strategies chosen in consultation with U.S. public health workers.

 

The first goal is to simulate the effectiveness of a set of potentially feasible intervention strategies. Combinations called targeted layered containment (TLC) of influenza antiviral treatment and prophylaxis and nonpharmaceutical interventions of quarantine, isolation, school closure, community social distancing, and workplace social distancing are considered.

 

The second goal is to examine the robustness of the results to model assumptions. The comparisons focus on a pandemic outbreak in a population similar to that of Chicago, with {approx}8.6 million people. The simulations suggest that at the expected transmissibility of a pandemic strain, timely implementation of a combination of targeted household antiviral prophylaxis, and social distancing measures could substantially lower the illness attack rate before a highly efficacious vaccine could become available.

 

Timely initiation of measures and school closure play important roles. Because of the current lack of data on which to base such models, further field research is recommended to learn more about the sources of transmission and the effectiveness of social distancing measures in reducing influenza transmission.

 

 

Using a combination of strategically applied antiviral medications, and early initiation of NPI's (Non-Pharmaceutical Interventions), this study indicates that the rate of infection in a large city (8.6 million people) could be reduced by as much as 80%.

 

 

 

 

 

Pandemic flu plan would put Chicago into lockdown

 

Published: Tuesday, 11 March, 2008

CHICAGO: Containing an influenza pandemic in a large US city like Chicago would require widespread school closings, quarantines of infected households and bans on public gatherings, US researchers said yesterday.

 


But, if done quickly and well, such steps could reduce infections by as much as 80%, said researcher Stephen Eubank of Virginia Tech in Blacksburg, Virginia, based on a computer simulation of just such an event.

 

“If you implement it early and people comply, you can save a lot of people. You can make it look a lot more like a seasonal flu than the 1918 pandemic,” said Eubank, referring to a global flu epidemic that started in 1918 and killed between 40mn and 100mn people.

<snip>

 

Schools and day-care centres would close. Theatres, bars, restaurants and ball parks would be shuttered.


 

Offices and factories would be open but hobbled as workers stay home to care for children. Infected people and their friends and families would be confined to their homes.


 

“We are not talking about simply shutting things down for a day or two like a snow day. It’s a sustained period for weeks or months,” he said.


 

“You wouldn’t go out to the movies. You wouldn’t congregate with people. You’d pretty much be staying home with the doors and windows battened down,” he said.

 

 

 

There would be a steep economic price to be paid for such a strategy, and there are serious issues of compliance and practicality.  How long can society, and the supply chain, function under these sorts of restrictions?

 

Obviously, not everyone will be able stay home with their `doors and windows battened down'.   Too many people are essential cogs in the machinery of our society.  

 

Still, should a pandemic erupt, people will have to accept that it won't be life as usual. 

 

Not even close.