Pandemic versus epidemic influenza mortality: a pattern of changing age distribution.
Almost all deaths related to current influenza epidemics occur among the elderly. However, mortality was greatest among the young during the 1918-1919 pandemic. This study compared the age distribution of influenza-related deaths in the United States during this century's three influenza A pandemics with that of the following epidemics. Half of influenza-related deaths during the 1968-1969 influenza A (H3N2) pandemic and large proportions of influenza-related deaths during the 1957-1958 influenza A (H2N2) and the 1918-1919 influenza A (H1N1) pandemics occurred among persons <65 years old. However, this group accounted for decrementally smaller proportions of deaths during the first decade following each pandemic. A model suggested that this mortality pattern may be explained by selective acquisition of protection against fatal illness among younger persons. The large proportion of influenza-related deaths during each pandemic and the following decade among persons <65 years old should be considered in planning for pandemics.
Simonsen
L
L
Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, US Department of Health & Human Services, Atlanta, Georgia 30333, USA. Lonesimon@msn.com
Clarke
M J
MJ
Schonberger
L B
LB
Arden
N H
NH
Cox
N J
NJ
Fukuda
K
K
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D002648:Child; D002675:Child, Preschool; D003198:Computer Simulation; D004196:Disease Outbreaks; D006801:Humans; D007223:Infant; D009980:Influenza A virus; D007251:Influenza, Human / Q000453:epidemiology / Q000401:mortality*; D008875:Middle Aged; D008954:Models, Biological; D012621:Seasons; D014481:United States / Q000453:epidemiology