Detecting the Shift in Mortality Toward Younger Age Group for Influenza Pandemics by Using 122 Cities Mortality Reporting System Data

• Activity Number: 675
• Type: Contributed
• Date/Time: Thursday, August 4, 2011 : 10:30 AM to 12:20 PM
• Sponsor: Section on Statistics in Epidemiology
• Author(s): Po-Yung Cheng*+ and Hong Zhou and Lynnette Brammer and David Shay
• Companies: Centers for Disease Control and Prevention and Centers for Disease Control and Prevention/AREF and Centers for Disease Control and Prevention and Centers for Disease Control and Prevention
• Keywords: negative binomial regression ; influenza ; pneumonia ; deaths

Abstract

To detect any shift in mortality patterns toward younger persons during pandemics, analyses of the timely 122 Cities Mortality Reporting System (122 CMRS) data may be useful. In this study, we used 122 CMRS data stratified by age group from 1962 through 2010. We compared the proportions of influenza deaths occurring among three age groups (0-24 years, 25-64 years and 65+ years) with total influenza deaths. We also compared influenza-associated pneumonia & influenza deaths for the same time period. The 2009 H1N1 pandemic, two severe H3N2 epidemics, and the 1968 pandemic seasons were specifically selected for comparison. The proportions of influenza deaths by age group for H1N1 pandemic were unique. For example, 64% of influenza deaths during the 2009 pandemic occurred among those aged 25-64 years. In contrast, only 12% of influenza deaths during severe H3N2 epidemics and 29% of influenza deaths during the 1968 pandemic occurred in this age group. When comparing influenza-associated deaths estimated by using negative binomial regression models, 48% occurred among those aged 25-64 years during the 2009 pandemic. Pandemics caused a substantial shift in mortality toward younger persons.