title: Viral shedding in patients infected with pandemic influenza A (H1N1) virus in Kenya, 2009.
abstract: BACKGROUND
  Understanding shedding patterns of 2009 pandemic influenza A (H1N1) (pH1N1) can inform recommendations about infection control measures. We evaluated the duration of pH1N1 virus shedding in patients in Nairobi, Kenya.
  
  
  METHODS
  Nasopharyngeal (NP) and oropharyngeal (OP) specimens were collected from consenting laboratory-confirmed pH1N1 cases every 2 days during October 14-November 25, 2009, and tested at the Centers for Diseases Control and Prevention-Kenya by real time reverse transcriptase polymerase chain reaction (rRT-PCR). A subset of rRT-PCR-positive samples was cultured.
  
  
  RESULTS
  Of 285 NP/OP specimens from patients with acute respiratory illness, 140 (49%) tested positive for pH1N1 by rRT-PCR; 106 (76%) patients consented and were enrolled. The median age was 6 years (Range: 4 months-41 years); only two patients, both asthmatic, received oseltamivir. The median duration of pH1N1 detection after illness onset was 8 days (95% CI: 7-10 days) for rRT-PCR and 3 days (Range: 0-13 days) for viral isolation. Viable pH1N1 virus was isolated from 132/162 (81%) of rRT-PCR-positive specimens, which included 118/125 (94%) rRT-PCR-positive specimens collected on day 0-7 after symptoms onset. Viral RNA was detectable in 18 (17%) and virus isolated in 7/18 (39%) of specimens collected from patients after all their symptoms had resolved.
  
  
  CONCLUSIONS
  In this cohort, pH1N1 was detected by rRT-PCR for a median of 8 days. There was a strong correlation between rRT-PCR results and virus isolation in the first week of illness. In some patients, pH1N1 virus was detectable after all their symptoms had resolved.
authors.affiliation: US Centers for Disease Control and Prevention-Kenya, Nairobi, Kenya. lwaiboci@ke.cdc.gov
authors.forename: Lilian W
authors.initials: LW
authors.lastname: Waiboci
authors.forename: Emmaculate
authors.initials: E
authors.lastname: Lebo
authors.forename: John M
authors.initials: JM
authors.lastname: Williamson
authors.forename: William
authors.initials: W
authors.lastname: Mwiti
authors.forename: Gilbert K
authors.initials: GK
authors.lastname: Kikwai
authors.forename: Henry
authors.initials: H
authors.lastname: Njuguna
authors.forename: Beatrice
authors.initials: B
authors.lastname: Olack
authors.forename: Robert F
authors.initials: RF
authors.lastname: Breiman
authors.forename: M Kariuki
authors.initials: MK
authors.lastname: Njenga
authors.forename: Mark A
authors.initials: MA
authors.lastname: Katz
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003710:Demography; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology*; D053208:Kaplan-Meier Estimate; D007630:Kenya / Q000453:epidemiology; D008297:Male; D058873:Pandemics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017201:Virus Shedding / Q000502:physiology*