title: Exploring the presentation of HPV information online: A semantic network analysis of websites.
abstract: BACKGROUND
  Negative vaccination-related information online leads some to opt out of recommended vaccinations.
  
  
  OBJECTIVE
  To determine how HPV vaccine information is presented online and what concepts co-occur.
  
  
  METHODS
  A semantic network analysis of the words in first-page Google search results was conducted using three negative, three neutral, and three positive search terms for 10 base concepts such as HPV vaccine, and HPV immunizations. In total, 223 of the 300 websites retrieved met inclusion requirements. Website information was analyzed using network statistics to determine what words most frequently appear, which words co-occur, and the sentiment of the words.
  
  
  RESULTS
  High levels of word interconnectivity were found suggesting a rich set of semantic links and a very integrated set of concepts. Limited number of words held centrality indicating limited concept prominence. This dense network signifies concepts that are well connected. Negative words were most prevalent and were associated with describing the HPV vaccine's side-effects as well as the negative effects of HPV and cervical cancer. A smaller cluster focuses on reporting negative vaccine side-effects. Clustering shows the words women and girls closely located to the words sexually, virus, and infection.
  
  
  CONCLUSIONS
  Information about the HPV vaccine online centered on a limited number of concepts. HPV vaccine benefits as well as the risks of HPV, including severity and susceptibility, were centrally presented. Word cluster results imply that HPV vaccine information for women and girls is discussed in more sexual terms than for men and boys.
authors.affiliation: Department of Communication, University of California, Davis, One Shields Ave., Davis, CA 95616, USA. Electronic address: jbruiz@ucdavis.edu.
authors.forename: Jeanette B
authors.initials: JB
authors.lastname: Ruiz
authors.affiliation: Department of Communication, University of California, Davis, One Shields Ave., Davis, CA 95616, USA. Electronic address: gabarnett@ucdavis.edu.
authors.forename: George A
authors.initials: GA
authors.lastname: Barnett
mesh_terms: D005260:Female; D006266:Health Education; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D020407:Internet; D008297:Male; D015233:Models, Statistical; D030361:Papillomavirus Infections / Q000150:complications / Q000453:epidemiology / Q000517:prevention & control*; D053918:Papillomavirus Vaccines / Q000009:adverse effects / Q000276:immunology*; D012660:Semantics; D012725:Sexual Behavior; D002583:Uterine Cervical Neoplasms / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D014611:Vaccination / Q000009:adverse effects / Q000379:methods* / Q000523:psychology
chemical_list: D053918:Papillomavirus Vaccines
keywords: Concept co-occurrence; HPV vaccine websites; Semantic network analysis