U.S. airport entry screening in response to pandemic influenza: Modeling and analysis

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doi:10.1016/j.tmaid.2009.02.006

Copyright © 2009 Elsevier Ltd All rights reserved



John D. Malone^{a, ,} , Robert Brigantic^b, George A. Muller^b, Ashok Gadgil^c, Woody Delp^c, Benjamin H. McMahon^d, Russell Lee^e, Jim Kulesz^e and F. Matthew Mihelic^e
aCenter for Disaster and Humanitarian Assistance Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814-4799, USA
^bPacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, WA 99352, USA
^cLawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
^dLos Alamos National Laboratory, 30 Bikini Atoll Road, Los Alamos, NM 87545, USA
^eOak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831, USA



Received 5 February 2009;
accepted 9 February 2009.
Available online 14 April 2009.

Summary

Background

A stochastic discrete event simulation model was developed to assess the effectiveness of passenger screening for Pandemic Influenza (PI) at U.S. airport foreign entry.
Methods

International passengers arriving at 18 U.S. airports from Asia, Europe, South America, and Canada were assigned to one of three states: not infected, infected with PI, infected with other respiratory illness. Passengers passed through layered screening then exited the model. 80% screening effectiveness was assumed for symptomatic passengers; 6% asymptomatic passengers.
Results

In the first 100 days of a global pandemic, U.S. airport screening would evaluate over 17 M passengers with 800 K secondary screenings. 11,570 PI infected passengers (majority asymptomatic) would enter the U.S. undetected from all 18 airports. Foreign airport departure screening significantly decreased the false negative (infected/undetected) passengers.

U.S. attack rates: no screening (26.9%–30.9%); screening (26.4%–30.6%); however airport screening results in 800 K–1.8 M less U.S. PI cases; 16 K–35 K less deaths (2% fatality rate). Antiviral medications for travel contact prophylaxis (10 contacts/PI passenger) were high – 8.8 M. False positives from all 18 airports: 100–200/day.

Conclusions

Foreign shore exit screening greatly reduces numbers of PI infected passengers. U.S. airport screening identifies 50% infected individuals; efficacy is limited by the asymptomatic PI infected. Screening will not significantly delay arrival of PI via international air transport, but will reduce the rate of new US cases and subsequent deaths.

Keywords: Pandemic influenza; Airport screening; Influenza transmission

Article Outline

Introduction

Materials and methods

Results

Discussion

Conflict of interest

Acknowledgements

References

hat-tip Florida1