title: Social Media as a Sentinel for Disease Surveillance: What Does Sociodemographic Status Have to Do with It?
abstract: BACKGROUND
  Data from social media have been shown to have utility in augmenting traditional approaches to public health surveillance. Quantifying the representativeness of these data is needed for making accurate public health inferences.
  
  
  METHODS
  We applied machine-learning methods to explore spatial and temporal dengue event reporting trends on Twitter relative to confirmed cases, and quantified associations with sociodemographic factors across three Brazilian states (São Paulo, Rio de Janeiro, and Minas Gerais) at the municipality level.
  
  
  RESULTS
  Education and income were positive predictors of dengue reporting on Twitter. In contrast, municipalities with a higher percentage of older adults, and males were less likely to report suspected dengue disease on Twitter. Overall, municipalities with dengue disease tweets had higher mean per capita income and lower proportion of individuals with no primary school education.
  
  
  CONCLUSIONS
  These observations highlight the need to understand population representation across locations, age, and racial/ethnic backgrounds in studies using social media data for public health research. Additional data is needed to assess and compare data representativeness across regions in Brazil.
authors.affiliation: Institute for Health Metrics and Evaluation, Global Health, University of Washington, Seattle, Washington, USA.
authors.forename: Elaine O
authors.initials: EO
authors.lastname: Nsoesie
authors.affiliation: Public Health Graduate Program, Escola Nacional de Saude Publica (ENSP/Fiocruz), Rio de Janeiro, Brazil.
authors.forename: Luisa
authors.initials: L
authors.lastname: Flor
authors.affiliation: Informatics Program (BCH); Pediatrics (HMS), Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Jared
authors.initials: J
authors.lastname: Hawkins
authors.affiliation: Biomedical & Health Informatics, University of Washington, Seattle, Washington, USA.
authors.forename: Adyasha
authors.initials: A
authors.lastname: Maharana
authors.affiliation: Health Policy and Management, Harvard School of Public Health, Boston, Massachusetts, USA.
authors.forename: Tobi
authors.initials: T
authors.lastname: Skotnes
authors.affiliation: NCDs and Health Promotion, Ministry of Health, Brasilia, Federal District, Brazil.
authors.forename: Fatima
authors.initials: F
authors.lastname: Marinho
authors.affiliation: Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: John S
authors.initials: JS
authors.lastname: Brownstein
keywords: Brazil; Twitter; dengue; disease surveillance; infectious disease; social medi; sociodemographic status; socioeconomic factors