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Volume 12, Number 1—January 2006
Research

Economics of Neuraminidase Inhibitor Stockpiling for Pandemic Influenza, Singapore

Vernon J. Lee*Comments to Author , Kai Hong Phua†, Mark I. Chen*, Angela Chow‡, Stefan Ma‡, Kee Tai Goh‡, and Yee Sin Leo*
Author affiliations: *Tan Tock Seng Hospital, Singapore; †National University of Singapore, Singapore; ‡Ministry of Health, Singapore

Main Article

Table 1

Input variables used in analysis*†

Input variables Age ranges, y
<19 20–64 >65 Sources
Average age 10 40 73 16
Population, ×1,000 persons 999.2 2,962.5 278.6 16
Low risk, % 90 89.7 63.3
High risk, %‡ 10 10.3 36.7 1720
Baseline influenzalike illness rate, cases/wk 7,686 19,940 750 2,21
Influenza clinical attack rate, % (range) 30 (10–50) 30 (10–50) 30 (10–50) 4,13,22,23
Case-fatality rate/100,000§ Ministry of Health 4,13,24,
Low risk 5 (1–12.5) 6 (1–9) 340 (28–680)
High risk 137 (12.6–765) 149 (10–570) 1,700 (276–3,400)
Earnings lost per death, $¶ 1,909,092 1,780,027 187,301 16,25
Hospitalization rate/100,000 infected# Ministry of Health
Low risk 210 (42–525) 72 (12–108) 1,634 (135–3,268)
High risk 210 (100–1,173) 234 (16–895) 2,167 (352–4,334)
Average length of hospital stay, d 3.88 (2.3–9.2) 4.61 (3.2–11.8) 6.20 (4.6–13.4) 13,24,26
Average additional days lost 2 (1–3) 2 (1–3) 2 (1–3) Local physicians
Hospital cost, $/d 342 342 342 Ministry of Health
Value of 1 lost day, $** 108 166/108 108 Ministry of Health, 25
Outpatient
Days lost from outpatient influenza 3 (1–5) 3 (1–5) 3 (1–5) 9,13,23,27
Consultation and outpatient treatment cost, $ 40 40 40 Local physicians
Value of 1 lost day, $** 108 166 108 Ministry of Health 25,
Treatment with oseltamivir
Sought early medical care, % 70 (50–90) 70 (50–90) 70 (50–90) 13,28
Case-fatality rate reduction, % 70 (50–90) 70 (50–90) 30 (20–90) 24,29
Hospitalization rate reduction, % 60 (50–90) 60 (50–90) 30 (20–90) 11,24
Lost days gained, d 1.0 (0.1–2.0) 1.0 (0.1–2.0) 1.0 (0.1–2.0) 7,9,24,28
Treatment cost, $ per course 31 31 31 Ministry of Health
Prophylaxis with oseltamivir
Efficacy of prophylaxis, % 70 (50–90) 70 (50–90) 70 (50–90) 12,30
Immunity after prophylaxis, % 35 (20–50) 35 (20–50) 35 (20–50) 12,30
Prophylaxis cost, $/wk 21.7 21.7 21.7 Ministry of Health
No. stockpile cycles to pandemic 2.25 (1–3.5) 2.25 (1–3.5) 2.25 (1–3.5) 31,32
Pandemic duration, wk 12 (6–24) 3234
Treatment stockpile, % of population†† 10–100
Prophylaxis stockpile, wk†† 2–24

*All healthcare costs are in 2004 Singapore dollars and were compounded by using the consumer price index for Singapore (16).
†Base-case values are given with the range used for analysis given in parentheses, where applicable. Input variables were modeled as triangular distributions centered on base values; minimum and maximum values are given by extreme values in ranges.
‡High risk includes asthma, chronic obstructive pulmonary disease, heart disease, and diabetes patients.
§Based on deaths among those with clinical influenza.
¶Average present value of future earnings lost per death of a person of average age in the age group.
#Rate is based on hospitalizations among those with clinical influenza. Ranges were calculated based on a factor of the base cases versus the death rate.
**$166 for lost work day, $108 for unspecified days lost (taking care of ill child or elderly person), and additional days lost after hospitalization.
††The treatment and prophylaxis stockpiles are decision variables, and the analyses were performed for a range of values to determine the preferred outcomes.

Main Article

References
  1. Gerdil  C. The annual production cycle for influenza vaccine. Vaccine. 2003;21:17769. DOIPubMedGoogle Scholar
  2. Ng  TP, Pwee  TH, Niti  M, Goh  LG. Influenza in Singapore: assessing the burden of illness in the community. Ann Acad Med Singapore. 2002;31:1828.PubMedGoogle Scholar
  3. Gust  ID, Hampson  AW, Lavanchy  D. Planning for the next pandemic of influenza. Rev Med Virol. 2001;11:5970. DOIPubMedGoogle Scholar
  4. van Genugten  MLL, Heijnen  MA, Jager  JC. Pandemic influenza and healthcare demand in the Netherlands: scenario analysis. Emerg Infect Dis. 2003;9:5318. DOIPubMedGoogle Scholar
  5. Muenning  PA, Khan  K. Cost-effectiveness of vaccination versus treatment of influenza in healthy adolescents and adults. Clin Infect Dis. 2001;33:187985. DOIPubMedGoogle Scholar
  6. Bridges  CB, Thompson  WW, Meltzer  MI, Reeve  GR, Talamonti  WJ, Cox  NJ, Effectiveness and cost-benefit of influenza vaccination of healthy working adults: a randomized controlled trial. JAMA. 2000;284:165563. DOIPubMedGoogle Scholar
  7. Lee  PY, Matchar  DB, Clements  DA, Huber  J, Hamilton  JD, Peterson  ED. Economic analysis of influenza vaccination and antiviral treatment for healthy working adults. Ann Intern Med. 2002;137:22531.PubMedGoogle Scholar
  8. Balicer  RD, Huerta  M, Davidovitch  N, Grotto  I. Cost-benefit of stockpiling drugs for influenza pandemic. Emerg Infect Dis. 2005;11:12802.PubMedGoogle Scholar
  9. Nicholson  KG, Aoki  FY, Osterhaus  AD, Trottier  S, Carewicz  O, Mercier  CH, Efficacy and safety of oseltamivir in treatment of acute influenza: a randomized controlled trial. Lancet. 2000;355:184550. DOIPubMedGoogle Scholar
  10. Massarella  JW, He  GZ, Dorr  A, Nieforth  K, Ward  P, Brown  A. The pharmacokinetics and tolerability of the oral neuraminidase inhibitor oseltamivir (Ro 64-0796/GS4104) in healthy adult and elderly volunteers. J Clin Pharmacol. 2000;40:83643. DOIPubMedGoogle Scholar
  11. Kaiser  L, Wat  C, Mills  T, Mahoney  P, Ward  P, Hayden  F. Impact of oseltamivir treatment on influenza-related lower respiratory tract complications and hospitalizations. Arch Intern Med. 2003;163:166772. DOIPubMedGoogle Scholar
  12. Hayden  FG, Atmar  RL, Schilling  M, Johnson  C, Poretz  D, Paar  D, Use of the selective oral neuraminidase inhibitor oseltamivir to prevent influenza. N Engl J Med. 1999;341:133643. DOIPubMedGoogle Scholar
  13. Meltzer  MI, Cox  NJ, Fukuda  K. The economic impact of pandemic influenza in the United States: priorities for intervention. Emerg Infect Dis. 1999;5:65971. DOIPubMedGoogle Scholar
  14. Lui  KJ, Kendal  AP. Impact of influenza epidemics on mortality in the United States from October 1972 to May 1985. Am J Public Health. 1987;77:7126. DOIPubMedGoogle Scholar
  15. Ammon  CE. Spanish flu epidemic in 1918 in Geneva, Switzerland. Euro Surveill. 2002;7:1902.PubMedGoogle Scholar
  16. Key statistics. Singapore Department of Statistics. [cited 2005 May 3]. Available from http://www.singstat.gov.sg/
  17. Tan  CH, Emmanuel  SC, Tan  BY, Jacob  E. Prevalence of diabetes and ethnic differences in cardiovascular risk factors. Diabetes Care. 1999;22:2417. DOIPubMedGoogle Scholar
  18. Ng  TP. Adult asthma prevalence, morbidity and mortality and their relationships with environmental and medical care factors in Singapore. Asian Pac J Allergy Immunol. 1999;17:12735.PubMedGoogle Scholar
  19. Heng  DM, Lee  J, Chew  SK, Tan  BY, Hughes  K, Chia  KS. Incidence of ischaemic heart disease and stroke in Chinese, Malays, and Indians in Singapore: Singapore Cardiovascular Cohort Study. Ann Acad Med Singapore. 2000;29:2316.PubMedGoogle Scholar
  20. Wang  XS, Tan  TN, Shek  LP, Chng  SY, Hia  CP, Ong  NB, The prevalence of asthma and allergies in Singapore; data from two ISAAC surveys seven years apart. Arch Dis Child. 2004;89:4236. DOIPubMedGoogle Scholar
  21. Emmanuel  SC, Phua  HP, Cheong  PY. 2001 survey on primary medical care in Singapore. Singapore Med J. 2004;45:199–213.
  22. Kadri  ZN. An outbreak of "Hong Kong flu" in Singapore. Singapore Med J. 1970;11:30–2.
  23. Glezen  WP. Emerging infections: pandemic influenza. Epidemiol Rev. 1996;18:6476.PubMedGoogle Scholar
  24. Turner  D, Wailoo  A, Nicholson  K, Cooper  N, Sutton  A, Abrams  K. Systematic review and economic decision modelling for the prevention and treatment of influenza A and B. Health Technol Assess. 2003;7:1182.PubMedGoogle Scholar
  25. Haddix  AC, Teutsh  SM, Corso  PS. Prevention effectiveness—a guide to decision analysis and economic evaluation. 2nd ed. New York: Oxford University Press; 2003.
  26. Lee  KH, Chin  NK, Tan  WC, Lim  TK. Hospitalised low risk community-acquired pneumonia: outcome and potential for cost-savings. Ann Acad Med Singapore. 1999;28:38991.PubMedGoogle Scholar
  27. Treanor  JJ, Hayden  FG, Vrooman  PS, Barbarash  R, Bettis  R, Riff  D, Efficacy and safety of the oral neuraminidase inhibitor oseltamivir in treating acute influenza: a randomized controlled trial. US Oral Neuraminidase Study Group. JAMA. 2000;283:101624. DOIPubMedGoogle Scholar
  28. Woodall  J, Rowson  KEK, McDonald  JC. Age and Asian influenza. BMJ. 1958;4:13168. DOIPubMedGoogle Scholar
  29. Bowles  SK, Lee  W, Simor  AE, Vearncombe  M, Loeb  M, Tamblyn  S, ; Oseltamivir Compassionate Use Program Group. Use of oseltamivir during influenza outbreaks in Ontario nursing homes, 1999–2000. J Am Geriatr Soc. 2002;50:60816. DOIPubMedGoogle Scholar
  30. Welliver  R, Monto  AS, Carewicz  O, Schatteman  E, Hassman  M, Hedrick  J, ; Oseltamivir Post Exposure Prophylaxis Investigator Group. Effectiveness of oseltamivir in preventing influenza in household contacts: a randomized controlled trial. JAMA. 2001;285:74854. DOIPubMedGoogle Scholar
  31. Doraisingham  S, Goh  KT, Ling  AE, Yu  M. Influenza surveillance in Singapore: 1972–86. Bull World Health Organ. 1988;66:5763.PubMedGoogle Scholar
  32. Scholtissek  C. Source for influenza pandemics. Eur J Epidemiol. 1994;10:4558. DOIPubMedGoogle Scholar
  33. Chew  FT, Doraisingham  S, Ling  AE, Kumarasinghe  G, Lee  BW. Seasonal trends of viral respiratory tract infections in the tropics. Epidemiol Infect. 1998;121:1218. DOIPubMedGoogle Scholar
  34. Nguyen-Van-Tam J. Epidemiology of influenza. In: Nicholson KG, Webster RG, Hay AJ, editors. Textbook of influenza. Oxford: Blackwell Science Ltd; 1998. p. 181–206.
  35. Chik  KW, Li  CK, Chan  PKS, Shing  MMK, Lee  V, Tam  JSL, Oseltamivir prophylaxis during the influenza season in a paediatric cancer centre: prospective observational study. Hong Kong Med J. 2004;10:1036.PubMedGoogle Scholar
  36. Govorkova  EA, Leneva  IA, Goloubeva  OG, Bush  K, Webster  RG. Comparison of efficacies of RWJ-270201, zanamivir, and oseltamivir against H5N1, H9N2, and other avian influenza viruses. Antimicrob Agents Chemother. 2001;45:272332. DOIPubMedGoogle Scholar
  37. McKimm-Breschkin  JL. Management of influenza virus infections with neuraminidase inhibitors: detection, incidence, and implications of drug resistance. Treat Respir Med. 2005;4:10716. DOIPubMedGoogle Scholar

Main Article

1"Dominate" is a term used in cost-effectiveness analyses and refers to a strategy that is both more efficacious and less costly than another strategy.

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