Prioritization of influenza pandemic vaccination to minimize years of life lost.
BACKGROUND
How to allocate limited vaccine supplies in the event of an influenza pandemic is currently under debate. Conventional vaccination strategies focus on those at highest risk for severe outcomes, including seniors, but do not consider (1) the signature pandemic pattern in which mortality risk is shifted to younger ages, (2) likely reduced vaccine response in seniors, and (3) differences in remaining years of life with age.


METHODS
We integrated these factors to project the age-specific years of life lost (YLL) and saved in a future pandemic, on the basis of mortality patterns from 3 historical pandemics, age-specific vaccine efficacy, and the 2000 US population structure.


RESULTS
For a 1918-like scenario, the absolute mortality risk is highest in people <45 years old; in contrast, seniors (those >or=65 years old) have the highest mortality risk in the 1957 and 1968 scenarios. The greatest YLL savings would be achieved by targeting different age groups in each scenario; people <45 years old in the 1918 scenario, people 45-64 years old in the 1968 scenario, and people >45 years old in the 1957 scenario.


CONCLUSIONS
Our findings shift the focus of pandemic vaccination strategies onto younger populations and illustrate the need for real-time surveillance of mortality patterns in a future pandemic. Flexible setting of vaccination priority is essential to minimize mortality.
Fogarty International Center, National Institutes of Health, Bethesda, Maryland 20892, USA. millemar@mail.nih.gov
Mark A
MA
Miller
Cecile
C
Viboud
Donald R
DR
Olson
Rebecca F
RF
Grais
Maia A
MA
Rabaa
Lone
L
Simonsen
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks / Q000517:prevention & control*; D006285:Health Planning; D006291:Health Policy; D006292:Health Priorities; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007252:Influenza Vaccines / Q000627:therapeutic use*; D007251:Influenza, Human / Q000401:mortality / Q000517:prevention & control*; D008875:Middle Aged; D015233:Models, Statistical; D014481:United States; D014611:Vaccination / Q000379:methods*
D007252:Influenza Vaccines