Effectiveness and cost-effectiveness of vaccination against pandemic influenza (H1N1) 2009.
BACKGROUND
Decisions on the timing and extent of vaccination against pandemic (H1N1) 2009 virus are complex.


OBJECTIVE
To estimate the effectiveness and cost-effectiveness of pandemic influenza (H1N1) vaccination under different scenarios in October or November 2009.


METHODS
Compartmental epidemic model in conjunction with a Markov model of disease progression.


METHODS
Literature and expert opinion.


METHODS
Residents of a major U.S. metropolitan city with a population of 8.3 million.


METHODS
Lifetime.


CONCLUSIONS
Societal.


METHODS
Vaccination in mid-October or mid-November 2009.


METHODS
Infections and deaths averted, costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness.


RESULTS
Assuming each primary infection causes 1.5 secondary infections, vaccinating 40% of the population in October or November would be cost-saving. Vaccination in October would avert 2051 deaths, gain 69 679 QALYs, and save $469 million compared with no vaccination; vaccination in November would avert 1468 deaths, gain 49 422 QALYs, and save $302 million.


RESULTS
Vaccination is even more cost-saving if longer incubation periods, lower rates of infectiousness, or increased implementation of nonpharmaceutical interventions delay time to the peak of the pandemic. Vaccination saves fewer lives and is less cost-effective if the epidemic peaks earlier than mid-October.


CONCLUSIONS
The model assumed homogenous mixing of case-patients and contacts; heterogeneous mixing would result in faster initial spread, followed by slower spread. Additional costs and savings not included in the model would make vaccination more cost-saving.


CONCLUSIONS
Earlier vaccination against pandemic (H1N1) 2009 prevents more deaths and is more cost-saving. Complete population coverage is not necessary to reduce the viral reproductive rate sufficiently to help shorten the pandemic.


BACKGROUND
Agency for Healthcare Research and Quality and National Institute on Drug Abuse.
Khazeni
Nayer
N
Division of Pulmonary and Critical Care Medicine, Stanford University Medical Center, 300 Pasteur Drive, H3143, Stanford, CA 94305, USA.
Hutton
David W
DW
Garber
Alan M
AM
Hupert
Nathaniel
N
Owens
Douglas K
DK
D003362:Cost-Benefit Analysis; D003661:Decision Support Techniques; D004196:Disease Outbreaks / Q000191:economics / Q000517:prevention & control*; D018450:Disease Progression; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007252:Influenza Vaccines / Q000009:adverse effects / Q000191:economics* / Q000600:supply & distribution; D007251:Influenza, Human / Q000191:economics / Q000453:epidemiology / Q000517:prevention & control*; D008297:Male; D008390:Markov Chains; D032541:Mass Vaccination / Q000191:economics*; D019057:Quality-Adjusted Life Years; D012621:Seasons; D012680:Sensitivity and Specificity; D013997:Time Factors; D014481:United States / Q000453:epidemiology
D007252:Influenza Vaccines