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Volume 13, Number 9—September 2007
Research

Frequent Travelers and Rate of Spread of Epidemics

T. Déirdre Hollingsworth*Comments to Author , Neil M. Ferguson*, and Roy M. Anderson*
Author affiliations: *Imperial College London, London, United Kingdom;

Main Article

Table 1

Parameter descriptions and values of epidemiologic model that simulates exportation of cases from SARS-like and influenza-like epidemics*

Description Parameter Value (reference)
SARS Influenza
Infection
Basic reproductive number R0 2.5 (13) 1.8 (14)
Latent period, d TL 4 (13) 1.5 (14)
Infectious period, d TI 10 (13) 1.1 (14)
Generation time, d Tg = TL + TI 14 2.6
Epidemic doubling time, d td = Tg / (R0 – 1) ln2 6.5 2.3
International travel
Proportion of population who are high-frequency fliers r 0–0.5
Mixing between groups: φ = 1, random mixing; φ = 0, 
 assortative mixing φ 0–1
Relative probability of flying of high-frequency fliers f 20
Mean probability of flying per day ε 0.005 (9)
Probability of flying per day of high-frequency fliers εH = f / 1 + (f – 1)r ε 0.084
Probability of flying per day of low-frequency fliers εL = 1 / 1 + (f – 1)r ε 0.042
Probability of a case being exported
Homogeneous flying patterns L = TLε 0.02 0.008
High-frequency fliers lH = TLεH 0.34 0.13
Low-frequency fliers lL = TLεL 0.017 0.006

*SARS, severe acute respiratory syndrome.

Main Article

References
  1. Denstadli  JM. Analysing air travel: a comparison of different survey methods and data collection procedures. J Travel Res. 2000;39:4–10. DOIGoogle Scholar
  2. Office for National Statistics. Travel trends 2004: a report on the international passenger survey. Basingstoke (UK): Palgrave Macmillan; 2005.
  3. Severe Acute Respiratory Syndrome (SARS) Expert Committee. SARS in Hong Kong: from experience to action: severe acute respiratory syndrome (SARS). Expert Committee of Hong Kong. 2003. [cited 2007 Jun 21]. Available from http://www.sars-expertcom.gov.hk/english/reports/reports.html
  4. Hufnagel  L, Brockmann  D, Geisel  T. Forecast and control of epidemics in a globalized world. Proc Natl Acad Sci U S A. 2004;101:15124–9. DOIPubMedGoogle Scholar
  5. Guimera  R, Mossa  S, Turtschi  A, Amaral  LA. The worldwide air transportation network: anomalous centrality, community structure, and cities’ global roles. Proc Natl Acad Sci U S A. 2005;102:7794–9. DOIPubMedGoogle Scholar
  6. Colizza  V, Barrat  A, Barthelemy  M, Vespignani  A. The role of the airline transportation network in the prediction and predictability of global epidemics. Proc Natl Acad Sci U S A. 2006;103:2015–20. DOIPubMedGoogle Scholar
  7. Pitman  RJ, Cooper  BS, Trotter  CL, Gay  NJ, Edmunds  WJ. Entry screening for severe acute respiratory syndrome (SARS) or influenza: policy evaluation. BMJ. 2005;331:1242–3. DOIPubMedGoogle Scholar
  8. Cooper  BS, Pitman  RJ, Edmunds  WJ, Gay  NJ. Delaying the international spread of pandemic influenza. PLoS Med. 2006;3:e212. DOIPubMedGoogle Scholar
  9. Hollingsworth  TD, Ferguson  NM, Anderson  RM. Will travel restrictions control the international spread of pandemic influenza? Nat Med. 2006;12:497–9. DOIPubMedGoogle Scholar
  10. Ferguson  NM, Cummings  DA, Fraser  C, Cajka  JC, Cooley  PC, Burke  DS. Strategies for mitigating an influenza pandemic. Nature. 2006;442:448–52. DOIPubMedGoogle Scholar
  11. Brownstein  JS, Wolfe  CJ, Mandl  KD. Empirical evidence for the effect of airline travel on inter-regional influenza spread in the United States. PLoS Med. 2006;3:e401. DOIPubMedGoogle Scholar
  12. Colizza  V, Barrat  A, Barthelemy  M, Valleron  AJ, Vespignani  A. Modeling the worldwide spread of pandemic influenza: baseline case and containment interventions. PLoS Med. 2007;4:e13. DOIPubMedGoogle Scholar
  13. Donnelly  CA, Fisher  MC, Fraser  C, Ghani  AC, Riley  S, Ferguson  NM, Epidemiological and genetic analysis of severe acute respiratory syndrome. Lancet Infect Dis. 2004;4:672–83. DOIPubMedGoogle Scholar
  14. Ferguson  NM, Cummings  DA, Cauchemez  S, Fraser  C, Riley  S, Meeyai  A, Strategies for containing an emerging influenza pandemic in Southeast Asia. Nature. 2005;437:209–14. DOIPubMedGoogle Scholar
  15. Anderson  RM, Fraser  C, Ghani  AC, Donnelly  CA, Riley  S, Ferguson  NM, Epidemiology, transmission dynamics and control of SARS: the 2002–2003 epidemic. Philos Trans R Soc Lond B Biol Sci. 2004;359:1091–105. DOIPubMedGoogle Scholar
  16. Yu  F, Le  MQ, Inoue  S, Thai  HT, Hasebe  F, Del Carmen Parquet  M, Evaluation of inapparent nosocomial severe acute respiratory syndrome coronavirus infection in Vietnam by use of highly specific recombinant truncated nucleocapsid protein-based enzyme-linked immunosorbent assay. Clin Diagn Lab Immunol. 2005;12:848–54.PubMedGoogle Scholar
  17. Wilder-Smith  A, Teleman  MD, Heng  BH, Earnest  A, Ling  AE, Leo  YS. Asymptomatic SARS coronavirus infection among healthcare workers, Singapore. Emerg Infect Dis. 2005;11:1142–5.PubMedGoogle Scholar
  18. Leung  GM, Lim  WW, Ho  LM, Lam  TH, Ghani  AC, Donnelly  CA, Seroprevalence of IgG antibodies to SARS-coronavirus in asymptomatic or subclinical population groups. Epidemiol Infect. 2006;134:211–21. DOIPubMedGoogle Scholar
  19. Leung  GM, Chung  PH, Tsang  T, Lim  W, Chan  SK, Chau  P, SARS-CoV antibody prevalence in all Hong Kong patient contacts. Emerg Infect Dis. 2004;10:1653–6.PubMedGoogle Scholar
  20. Lee  PP, Wong  WH, Leung  GM, Chiu  SS, Chan  KH, Peiris  JS, Risk-stratified seroprevalence of severe acute respiratory syndrome coronavirus among children in Hong Kong. Pediatrics. 2006;117:e1156–62. DOIPubMedGoogle Scholar
  21. Centers for Disease Control and Prevention. Prevalence of IgG antibody to SARS-associated coronavirus in animal traders—Guangdong Province, China, 2003. MMWR Morb Mortal Wkly Rep. 2003;52:986–7.PubMedGoogle Scholar
  22. Longini  IM Jr, Nizam  A, Xu  S, Ungchusak  K, Hanshaoworakul  W, Cummings  DA, Containing pandemic influenza at the source. Science. 2005;309:1083–7. DOIPubMedGoogle Scholar
  23. Germann  TC, Kadau  K, Longini  IM Jr, Macken  CA. Mitigation strategies for pandemic influenza in the United States. Proc Natl Acad Sci U S A. 2006;103:5935–40. DOIPubMedGoogle Scholar
  24. Bell  DM; World Health Organization Writing Group. Nonpharmaceutical interventions for pandemic influenza, international measures. Emerg Infect Dis. 2006;12:81–7.PubMedGoogle Scholar

Main Article

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