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Epidemiol Infect. 2016 Mar 9:1-6. [Epub ahead of print]
Enhanced risk of illness during the 1918 influenza pandemic after previous influenza-like illnesses in three military populations.
Shanks GD1, Burroughs SA2, Sohn JD3, Waters NC2, Smith VF3, Waller M4, Brundage JF5.
Author information
Abstract
The reasons for the unprecedented mortality during the 1918 influenza pandemic remain poorly understood. We examined morbidity records from three military cohorts from years prior to and during the 1918 pandemic period to assess the effects of previous respiratory illnesses on experiences during the pandemic. Clinical registers and morbidity lists were examined to identify all medical encounters for acute respiratory illnesses in students at two U.S. military officer training academies and Australian soldiers deployed in Europe. Influenza-like illness prior to the major pandemic wave of 1918 predisposed Australian soldiers [relative risk (RR) 1?37, 95% confidence interval (CI) 1?18-1?60, P < 0?0001] and US officer trainees at West Point (RR 3?10, 95% CI 2?13-4?52, P < 0?0001) and Annapolis (RR 2?03, 95% CI 1?65-2?50, P < 0?0001) to increased risks of medically treated illnesses in late 1918. The findings suggest that susceptibility to and/or clinical expressions of the 1918 pandemic influenza virus depended on previous experiences with respiratory infectious agents. The findings are consistent with observations during the 2009 pandemic in Canada and may reflect antibody-dependent enhancement of influenza infection.
KEYWORDS:
1918 pandemic; influenza; military; mortality
PMID: 26957052 [PubMed - as supplied by publisher]
Enhanced risk of illness during the 1918 influenza pandemic after previous influenza-like illnesses in three military populations.
Shanks GD1, Burroughs SA2, Sohn JD3, Waters NC2, Smith VF3, Waller M4, Brundage JF5.
Author information
Abstract
The reasons for the unprecedented mortality during the 1918 influenza pandemic remain poorly understood. We examined morbidity records from three military cohorts from years prior to and during the 1918 pandemic period to assess the effects of previous respiratory illnesses on experiences during the pandemic. Clinical registers and morbidity lists were examined to identify all medical encounters for acute respiratory illnesses in students at two U.S. military officer training academies and Australian soldiers deployed in Europe. Influenza-like illness prior to the major pandemic wave of 1918 predisposed Australian soldiers [relative risk (RR) 1?37, 95% confidence interval (CI) 1?18-1?60, P < 0?0001] and US officer trainees at West Point (RR 3?10, 95% CI 2?13-4?52, P < 0?0001) and Annapolis (RR 2?03, 95% CI 1?65-2?50, P < 0?0001) to increased risks of medically treated illnesses in late 1918. The findings suggest that susceptibility to and/or clinical expressions of the 1918 pandemic influenza virus depended on previous experiences with respiratory infectious agents. The findings are consistent with observations during the 2009 pandemic in Canada and may reflect antibody-dependent enhancement of influenza infection.
KEYWORDS:
1918 pandemic; influenza; military; mortality
PMID: 26957052 [PubMed - as supplied by publisher]