title: Incidence of Dengue Virus Infection in Adults and Children in a Prospective Longitudinal Cohort in the Philippines.
abstract: BACKGROUND
  The mean age of dengue has been increasing in some but not all countries. We sought to determine the incidence of dengue virus (DENV) infection in adults and children in a prospective cohort study in the Philippines where dengue is hyperendemic.
  
  
  RESULTS
  A prospective cohort of subjects ≥6 months old in Cebu City, Philippines, underwent active community-based surveillance for acute febrile illnesses by weekly contact. Fever history within the prior seven days was evaluated with an acute illness visit followed by 2, 5, and 8-day, and 3-week convalescent visits. Blood was collected at the acute and 3-week visits. Scheduled visits took place at enrolment and 12 months that included blood collections. Acute samples were tested by DENV PCR and acute/convalescent samples by DENV IgM/IgG ELISA to identify symptomatic infections. Enrolment and 12-month samples were tested by DENV hemagglutination inhibition (HAI) assay to identify subclinical infections. Of 1,008 enrolled subjects, 854 completed all study activities at 12 months per-protocol undergoing 868 person-years of surveillance. The incidence of symptomatic and subclinical infections was 1.62 and 7.03 per 100 person-years, respectively. However, in subjects >15 years old, only one symptomatic infection occurred whereas 27 subclinical infections were identified. DENV HAI seroprevalence increased sharply with age with baseline multitypic HAIs associated with fewer symptomatic infections. Using a catalytic model, the historical infection rate among dengue naïve individuals was estimated to be high at 11-22%/year.
  
  
  CONCLUSIONS
  In this hyperendemic area with high seroprevalence of multitypic DENV HAIs in adults, symptomatic dengue rarely occurred in individuals older than 15 years. Our findings demonstrate that dengue is primarily a pediatric disease in areas with high force of infection. However, the average age of dengue could increase if force of infection decreases over time, as is occurring in some hyperendemic countries such as Thailand.
authors: Philippines-AFRIMS Virology Research Unit, CAP Building, Cebu City, Philippines.
authors: Maria Theresa
authors: MT
authors: Alera
authors: Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America.
authors: Anon
authors: A
authors: Srikiatkhachorn
authors: Philippines-AFRIMS Virology Research Unit, CAP Building, Cebu City, Philippines.
authors: John Mark
authors: JM
authors: Velasco
authors: Cebu City Health Department, Cebu City, Philippines.
authors: Ilya A
authors: IA
authors: Tac-An
authors: Philippines-AFRIMS Virology Research Unit, CAP Building, Cebu City, Philippines.
authors: Catherine B
authors: CB
authors: Lago
authors: Department of Epidemiology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America.
authors: Hannah E
authors: HE
authors: Clapham
authors: Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.
authors: Stefan
authors: S
authors: Fernandez
authors: Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.
authors: Jens W
authors: JW
authors: Levy
authors: Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.
authors: Butsaya
authors: B
authors: Thaisomboonsuk
authors: Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.
authors: Chonticha
authors: C
authors: Klungthong
authors: Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.
authors: Louis R
authors: LR
authors: Macareo
authors: Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.
authors: Ananda
authors: A
authors: Nisalak
authors: Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.|Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors: Laura
authors: L
authors: Hermann
authors: Cebu City Health Department, Cebu City, Philippines.
authors: Daisy
authors: D
authors: Villa
authors: Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.|Dengue Vaccine Initiative, International Vaccine Institute, Seoul, Korea.
authors: In-Kyu
authors: IK
authors: Yoon
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000097:blood; D058345:Asymptomatic Infections / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D003715:Dengue / Q000453:epidemiology* / Q000276:immunology / Q000473:pathology / Q000821:virology; D003716:Dengue Virus / Q000276:immunology / Q000302:isolation & purification; D019353:Endemic Diseases; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D015994:Incidence; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010679:Philippines / Q000453:epidemiology; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification; D016036:Seroepidemiologic Studies; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D012367:RNA, Viral