title: Results from the first six years of national sentinel surveillance for influenza in Kenya, July 2007-June 2013.
abstract: BACKGROUND
  Recent studies have shown that influenza is associated with significant disease burden in many countries in the tropics, but until recently national surveillance for influenza was not conducted in most countries in Africa.
  
  
  METHODS
  In 2007, the Kenyan Ministry of Health with technical support from the CDC-Kenya established a national sentinel surveillance system for influenza. At 11 hospitals, for every hospitalized patient with severe acute respiratory illness (SARI), and for the first three outpatients with influenza-like illness (ILI) per day, we collected both nasopharyngeal and oropharyngeal swabs. Beginning in 2008, we conducted in-hospital follow-up for SARI patients to determine outcome. Specimens were tested by real time RT-PCR for influenza A and B. Influenza A-positive specimens were subtyped for H1, H3, H5, and (beginning in May 2009) A(H1N1)pdm09.
  
  
  RESULTS
  From July 1, 2007 through June 30, 2013, we collected specimens from 24,762 SARI and 14,013 ILI patients. For SARI and ILI case-patients, the median ages were 12 months and 16 months, respectively, and 44% and 47% were female. In all, 2,378 (9.6%) SARI cases and 2,041 (14.6%) ILI cases were positive for influenza viruses. Most influenza-associated SARI cases (58.6%) were in children <2 years old. Of all influenza-positive specimens, 78% were influenza A, 21% were influenza B, and 1% were influenza A/B coinfections. Influenza circulated in every month. In four of the six years influenza activity peaked during July-November. Of 9,419 SARI patients, 2.7% died; the median length of hospitalization was 4 days.
  
  
  CONCLUSIONS
  During six years of surveillance in Kenya, influenza was associated with nearly 10 percent of hospitalized SARI cases and one-sixth of outpatient ILI cases. Most influenza-associated SARI and ILI cases were in children <2 years old; interventions to reduce the burden of influenza, such as vaccine, could consider young children as a priority group.
authors: Centers for Disease Control and Prevention-Kenya/Kenya Medical Research Institute, Nairobi, Kenya.
authors: Mark A
authors: MA
authors: Katz
authors: Kenya Ministry of Health, Nairobi, Kenya.
authors: Philip
authors: P
authors: Muthoka
authors: Centers for Disease Control and Prevention-Kenya/Kenya Medical Research Institute, Nairobi, Kenya.
authors: Gideon O
authors: GO
authors: Emukule
authors: Kenya Ministry of Health, Nairobi, Kenya.
authors: Rosalia
authors: R
authors: Kalani
authors: Centers for Disease Control and Prevention-Kenya/Kenya Medical Research Institute, Nairobi, Kenya.
authors: Henry
authors: H
authors: Njuguna
authors: Centers for Disease Control and Prevention-Kenya/Kenya Medical Research Institute, Nairobi, Kenya.
authors: Lilian W
authors: LW
authors: Waiboci
authors: Centers for Disease Control and Prevention-Kenya/Kenya Medical Research Institute, Nairobi, Kenya.
authors: Jamal A
authors: JA
authors: Ahmed
authors: Centers for Disease Control and Prevention-Kenya/Kenya Medical Research Institute, Nairobi, Kenya.
authors: Godfrey
authors: G
authors: Bigogo
authors: Centers for Disease Control and Prevention-Kenya/Kenya Medical Research Institute, Nairobi, Kenya.
authors: Daniel R
authors: DR
authors: Feikin
authors: Centers for Disease Control and Prevention-Kenya/Kenya Medical Research Institute, Nairobi, Kenya.
authors: Moses K
authors: MK
authors: Njenga
authors: Centers for Disease Control and Prevention-Kenya/Kenya Medical Research Institute, Nairobi, Kenya.
authors: Robert F
authors: RF
authors: Breiman
authors: Centers for Disease Control and Prevention-Kenya/Kenya Medical Research Institute, Nairobi, Kenya.
authors: Joshua A
authors: JA
authors: Mott
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D003710:Demography; D005260:Female; D005843:Geography; D006801:Humans; D007223:Infant; D007251:Influenza, Human / Q000453:epidemiology*; D007630:Kenya / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012621:Seasons; D018571:Sentinel Surveillance; D045169:Severe Acute Respiratory Syndrome / Q000453:epidemiology; D055815:Young Adult