title: Incidence and Risk Factors for Respiratory Syncytial Virus and Human Metapneumovirus Infections among Children in the Remote Highlands of Peru.
abstract: BACKGROUND
  The disease burden and risk factors for respiratory syncytial virus (RSV) and human metapneumovirus (MPV) infections among children living in remote, rural areas remain unclear.
  
  
  METHODS
  We conducted a prospective, household-based cohort study of children aged <3 years living in remote rural highland communities in San Marcos, Cajamarca, Peru. Acute respiratory illnesses (ARI), including lower respiratory tract infection (LRTI), were monitored through weekly household visits from March 2009 through September 2011. Nasal swabs collected during ARI/LRTI were tested for RSV, MPV, and other respiratory viruses using real-time RT-PCR. Incidence rates and rate ratios were calculated using mixed effects Poisson regression.
  
  
  RESULTS
  Among 892 enrolled children, incidence rates of RSV and MPV ARI were 30 and 17 episodes per 100 child-years, respectively. The proportions of RSV and MPV ARI that presented as LRTI were 12.5% and 8.9%, respectively. Clinic visits for ARI and hospitalizations were significantly more frequent (all p values <0.05) among children with RSV (clinic 41% and hospital 5.3%) and MPV ARI (38% and 3.5%) when compared with other viral infections (23% and 0.7%) and infections without virus detected (24% and 0.6%). In multivariable analysis, risk factors for RSV detection included younger age (RR 1.02, 95% CI: 1.00-1.03), the presence of a smoker in the house (RR 1.63, 95% CI: 1.12-2.38), residing at higher altitudes (RR 1.93, 95% CI: 1.25-3.00 for 2nd compared to 1st quartile residents; RR 1.98, 95% CI: 1.26-3.13 for 3rd compared to 1st quartile residents). Having an unemployed household head was significantly associated with MPV risk (RR 2.11, 95% CI: 1.12-4.01).
  
  
  CONCLUSIONS
  In rural high altitude communities in Peru, childhood ARI due to RSV or MPV were common and associated with higher morbidity than ARI due to other viruses or with no viral detections. The risk factors identified in this study may be considered for interventional studies to control infections by these viruses among young children from developing countries.
authors.affiliation: School of Medicine, Vanderbilt University, Nashville, Tennessee, United States of America.
authors.forename: Andrew
authors.initials: A
authors.lastname: Wu
authors.affiliation: Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri, United States of America.
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Budge
authors.affiliation: Department of Pediatrics, Vanderbilt University, Nashville, Tennessee, United States of America; Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, Tennessee, United States of America.
authors.forename: John
authors.initials: J
authors.lastname: Williams
authors.affiliation: Department of Health Policy, Vanderbilt University, Nashville, Tennessee, United States of America.
authors.forename: Marie R
authors.initials: MR
authors.lastname: Griffin
authors.affiliation: Department of Pediatrics, Vanderbilt University, Nashville, Tennessee, United States of America; Vanderbilt Vaccine Research Program, Division of Infectious Diseases, Department of Pediatrics, Vanderbilt University, Nashville, Tennessee, United States of America.
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Edwards
authors.affiliation: Department of Pediatrics, Vanderbilt University, Nashville, Tennessee, United States of America.
authors.forename: Monika
authors.initials: M
authors.lastname: Johnson
authors.affiliation: Department of Biostatistics, Vanderbilt University, Nashville, Tennessee, United States of America.
authors.forename: Yuwei
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Swiss Tropical and Public Health Institute, Basel, Switzerland; Instituto de Investigación Nutricional, Lima, Peru.
authors.forename: Stella
authors.initials: S
authors.lastname: Hartinger
authors.affiliation: Instituto de Investigación Nutricional, Lima, Peru.
authors.forename: Hector
authors.initials: H
authors.lastname: Verastegui
authors.affiliation: Instituto de Investigación Nutricional, Lima, Peru.
authors.forename: Ana I
authors.initials: AI
authors.lastname: Gil
authors.affiliation: Instituto de Investigación Nutricional, Lima, Peru.
authors.forename: Claudio F
authors.initials: CF
authors.lastname: Lanata
authors.affiliation: Department of Health Policy, Vanderbilt University, Nashville, Tennessee, United States of America.
authors.forename: Carlos G
authors.initials: CG
authors.lastname: Grijalva
mesh_terms: D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D029121:Metapneumovirus; D015999:Multivariate Analysis; D018184:Paramyxoviridae Infections / Q000453:epidemiology*; D010568:Peru / Q000453:epidemiology; D016012:Poisson Distribution; D011446:Prospective Studies; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology*; D018113:Respiratory Syncytial Virus, Human; D012307:Risk Factors; D012424:Rural Population