title: Disease detection or public opinion reflection? Content analysis of tweets, other social media, and online newspapers during the measles outbreak in The Netherlands in 2013.
abstract: BACKGROUND
  In May 2013, a measles outbreak began in the Netherlands among Orthodox Protestants who often refuse vaccination for religious reasons.
  
  
  OBJECTIVE
  Our aim was to compare the number of messages expressed on Twitter and other social media during the measles outbreak with the number of online news articles and the number of reported measles cases to answer the question if and when social media reflect public opinion patterns versus disease patterns.
  
  
  METHODS
  We analyzed measles-related tweets, other social media messages, and online newspaper articles over a 7-month period (April 15 to November 11, 2013) with regard to topic and sentiment. Thematic analysis was used to structure and analyze the topics.
  
  
  RESULTS
  There was a stronger correlation between the weekly number of social media messages and the weekly number of online news articles (P<.001 for both tweets and other social media messages) than between the weekly number of social media messages and the weekly number of reported measles cases (P=.003 and P=.048 for tweets and other social media messages, respectively), especially after the summer break. All data sources showed 3 large peaks, possibly triggered by announcements about the measles outbreak by the Dutch National Institute for Public Health and the Environment and statements made by well-known politicians. Most messages informed the public about the measles outbreak (ie, about the number of measles cases) (93/165, 56.4%) followed by messages about preventive measures taken to control the measles spread (47/132, 35.6%). The leading opinion expressed was frustration regarding people who do not vaccinate because of religious reasons (42/88, 48%).
  
  
  CONCLUSIONS
  The monitoring of online (social) media might be useful for improving communication policies aiming to preserve vaccination acceptability among the general public. Data extracted from online (social) media provide insight into the opinions that are at a certain moment salient among the public, which enables public health institutes to respond immediately and appropriately to those public concerns. More research is required to develop an automatic coding system that captures content and user's characteristics that are most relevant to the diseases within the National Immunization Program and related public health events and can inform official responses.
authors.affiliation: National Institute for Public Health and the Environment, Center for Infectious Disease Control, Bilthoven, Netherlands. Liesbeth.Mollema@rivm.nl.
authors.forename: Liesbeth
authors.identifier: http://orcid.org/0000-0003-2868-0821
authors.initials: L
authors.lastname: Mollema
authors.forename: Irene Anhai
authors.identifier: http://orcid.org/0000-0002-4443-3962
authors.initials: IA
authors.lastname: Harmsen
authors.forename: Emma
authors.identifier: http://orcid.org/0000-0002-9747-0505
authors.initials: E
authors.lastname: Broekhuizen
authors.forename: Rutger
authors.identifier: http://orcid.org/0000-0002-8427-1304
authors.initials: R
authors.lastname: Clijnk
authors.forename: Hester
authors.identifier: http://orcid.org/0000-0001-9100-1639
authors.initials: H
authors.lastname: De Melker
authors.forename: Theo
authors.identifier: http://orcid.org/0000-0003-4978-6246
authors.initials: T
authors.lastname: Paulussen
authors.forename: Gerjo
authors.identifier: http://orcid.org/0000-0002-3501-4096
authors.initials: G
authors.lastname: Kok
authors.forename: Robert
authors.identifier: http://orcid.org/0000-0001-5017-3258
authors.initials: R
authors.lastname: Ruiter
authors.forename: Enny
authors.identifier: http://orcid.org/0000-0002-0367-6757
authors.initials: E
authors.lastname: Das
mesh_terms: D000328:Adult; D001294:Attitude to Health; D004196:Disease Outbreaks; D006801:Humans; D008457:Measles / Q000453:epidemiology*; D009426:Netherlands / Q000453:epidemiology; D009524:Newspapers as Topic; D010342:Patient Acceptance of Health Care; D011634:Public Health; D011639:Public Opinion; D061108:Social Media; D014611:Vaccination / Q000523:psychology
keywords: Internet; Netherlands; Web 2.0; infectious disease outbreak; measles; vaccination