title: Correlation between National Influenza Surveillance Data and Search Queries from Mobile Devices and Desktops in South Korea.
abstract: BACKGROUND
  Digital surveillance using internet search queries can improve both the sensitivity and timeliness of the detection of a health event, such as an influenza outbreak. While it has recently been estimated that the mobile search volume surpasses the desktop search volume and mobile search patterns differ from desktop search patterns, the previous digital surveillance systems did not distinguish mobile and desktop search queries. The purpose of this study was to compare the performance of mobile and desktop search queries in terms of digital influenza surveillance.
  
  
  RESULTS
  The study period was from September 6, 2010 through August 30, 2014, which consisted of four epidemiological years. Influenza-like illness (ILI) and virologic surveillance data from the Korea Centers for Disease Control and Prevention were used. A total of 210 combined queries from our previous survey work were used for this study. Mobile and desktop weekly search data were extracted from Naver, which is the largest search engine in Korea. Spearman's correlation analysis was used to examine the correlation of the mobile and desktop data with ILI and virologic data in Korea. We also performed lag correlation analysis. We observed that the influenza surveillance performance of mobile search queries matched or exceeded that of desktop search queries over time. The mean correlation coefficients of mobile search queries and the number of queries with an r-value of ≥ 0.7 equaled or became greater than those of desktop searches over the four epidemiological years. A lag correlation analysis of up to two weeks showed similar trends.
  
  
  CONCLUSIONS
  Our study shows that mobile search queries for influenza surveillance have equaled or even become greater than desktop search queries over time. In the future development of influenza surveillance using search queries, the recognition of changing trend of mobile search data could be necessary.
authors.affiliation: Department of Biomedical Informatics, Asan Medical Center, Seoul 138-736, Korea.
authors.forename: Soo-Yong
authors.initials: SY
authors.lastname: Shin
authors.affiliation: Department of Emergency Medicine, University of Ulsan, College of Medicine, Asan Medical Center, Seoul 138-736, Korea.
authors.forename: Taerim
authors.initials: T
authors.lastname: Kim
authors.affiliation: Department of Emergency Medicine, University of Ulsan, College of Medicine, Asan Medical Center, Seoul 138-736, Korea.
authors.forename: Dong-Woo
authors.initials: DW
authors.lastname: Seo
authors.affiliation: Department of Emergency Medicine, University of Ulsan, College of Medicine, Asan Medical Center, Seoul 138-736, Korea.
authors.forename: Chang Hwan
authors.initials: CH
authors.lastname: Sohn
authors.affiliation: Department of Anesthesiology and Pain Medicine, University of Ulsan, College of Medicine, Asan Medical Center, Seoul 138-736, Korea.
authors.forename: Sung-Hoon
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Emergency Medicine, University of Ulsan, College of Medicine, Asan Medical Center, Seoul 138-736, Korea.
authors.forename: Seung Mok
authors.initials: SM
authors.lastname: Ryoo
authors.affiliation: Department of Emergency Medicine, University of Ulsan, College of Medicine, Asan Medical Center, Seoul 138-736, Korea.
authors.forename: Yoon-Seon
authors.initials: YS
authors.lastname: Lee
authors.affiliation: Department of Biomedical Informatics, Asan Medical Center, Seoul 138-736, Korea.|Department of Emergency Medicine, University of Ulsan, College of Medicine, Asan Medical Center, Seoul 138-736, Korea.
authors.forename: Jae Ho
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Emergency Medicine, University of Ulsan, College of Medicine, Asan Medical Center, Seoul 138-736, Korea.
authors.forename: Won Young
authors.initials: WY
authors.lastname: Kim
authors.affiliation: Department of Emergency Medicine, University of Ulsan, College of Medicine, Asan Medical Center, Seoul 138-736, Korea.
authors.forename: Kyoung Soo
authors.initials: KS
authors.lastname: Lim
mesh_terms: D004196:Disease Outbreaks / Q000706:statistics & numerical data; D006801:Humans; D007251:Influenza, Human; D057226:Information Seeking Behavior; D020407:Internet; D008838:Microcomputers / Q000706:statistics & numerical data*; D011159:Population Surveillance; D056910:Republic of Korea; D057386:Search Engine / Q000706:statistics & numerical data; D000068997:Smartphone / Q000706:statistics & numerical data*