title: Pandemic influenza virus 2009 H1N1 and adenovirus in a high risk population of young adults: epidemiology, comparison of clinical presentations, and coinfection.
abstract: BACKGROUND
  In 2009, pandemic H1N1 influenza virus (2009 H1N1) emerged worldwide, causing morbidity and mortality that disproportionately affected young adults. Upper respiratory infection (URI), largely due to adenovirus, is an endemic cause of morbidity in military training. Whether clinical presentations differ or excess morbidity results from coinfection is unclear.
  
  
  METHODS
  The Center for Advanced Molecular Detection evaluates epidemiology and rapid diagnostics of respiratory pathogens in trainees with URI. From May 1, 2009, to November 30, 2009, demographic, clinical, and PCR data from throat and nasal specimens for adenovirus and 2009 H1N1 were prospectively collected.
  
  
  RESULTS
  375 trainees with URI enrolled and were tested for both adenovirus and 2009 H1N1 by PCR (median age 20; 89% male). Adenovirus PCR was positive in 72% (96% serotype E-4) and 2009 H1N1 in 20%. Males were more likely to have adenovirus and females more likely to have 2009 H1N1 (p  =  0.047). Subjects with 2009 H1N1 presented an average of 1 week earlier in training, had shorter illness duration before enrollment, less sore throat, diarrhea, and fewer abnormal findings on throat exam. Coryza and cough were more common with 2009 H1N1 compared to adenovirus. Subjects with 2009 H1N1 were less likely to have adenovirus than those without, despite persistently high frequencies of adenovirus detections during peak 2009 H1N1 weeks (15% vs. 83%, p < 0.01). Coinfection with adenovirus and 2009 H1N1 was rare (4%). Rates of hospitalization and pneumonia did not differ between the adenovirus, 2009 H1N1, or coinfected groups.
  
  
  CONCLUSIONS
  Military trainees with 2009 H1N1 vs. adenovirus have differing clinical presentations, and males are more likely to have adenovirus. Despite high frequencies of adenovirus infection, coinfection with adenovirus and 2009 H1N1 is rare and apparently does not result in increased morbidity.
authors.affiliation: San Antonio Military Medical Center, Joint Base San Antonio Fort Sam Houston, Texas, United States of America ; Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America.
authors.forename: Heather C
authors.initials: HC
authors.lastname: Yun
authors.affiliation: Center for Advanced Molecular Detection, 59th MDW/ST, Joint Base San Antonio-Lackland, Texas, United States of America.
authors.forename: William H
authors.initials: WH
authors.lastname: Fugate
authors.affiliation: San Antonio Military Medical Center, Joint Base San Antonio Fort Sam Houston, Texas, United States of America ; Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America.
authors.forename: Clinton K
authors.initials: CK
authors.lastname: Murray
authors.affiliation: Trainee Health Surveillance, Joint Base San Antonio-Lackland, Texas, United States of America.
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Cropper
authors.affiliation: Center for Advanced Molecular Detection, 59th MDW/ST, Joint Base San Antonio-Lackland, Texas, United States of America.
authors.forename: Lisa
authors.initials: L
authors.lastname: Lott
authors.affiliation: Center for Advanced Molecular Detection, 59th MDW/ST, Joint Base San Antonio-Lackland, Texas, United States of America.
authors.forename: J Matthew
authors.initials: JM
authors.lastname: McDonald
mesh_terms: D000256:Adenoviridae / Q000502:physiology; D000257:Adenoviridae Infections / Q000453:epidemiology* / Q000473:pathology / Q000821:virology; D000293:Adolescent; D015897:Comorbidity; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000502:physiology; D007251:Influenza, Human / Q000453:epidemiology* / Q000473:pathology / Q000821:virology; D008297:Male; D008889:Military Personnel; D058873:Pandemics; D015995:Prevalence; D012141:Respiratory Tract Infections / Q000453:epidemiology* / Q000473:pathology / Q000821:virology; D012737:Sex Factors; D014481:United States / Q000453:epidemiology; D055815:Young Adult