title: Use of Internet Search Data to Monitor Rotavirus Vaccine Impact in the United States, United Kingdom, and Mexico.
abstract: BACKGROUND
  Previous studies have found a strong correlation between internet search and public health surveillance data. Less is known about how search data respond to public health interventions, such as vaccination, and the consistency of responses in different countries. In this study, we aimed to study the correlation between internet searches for "rotavirus" and rotavirus disease activity in the United States, United Kingdom, and Mexico before and after introduction of rotavirus vaccine.
  
  
  METHODS
  We compared time series of internet searches for "rotavirus" from Google Trends with rotavirus laboratory reports from the United States and United Kingdom and with hospitalizations for acute gastroenteritis in the United States and Mexico. Using time and location parameters, Google quantifies an internet query share (IQS) to measure the relative search volume for specific terms. We analyzed the correlation between IQS and laboratory and hospitalization data before and after national vaccine introductions.
  
  
  RESULTS
  There was a strong positive correlation between the rotavirus IQS and laboratory reports in the United States (R2 = 0.79) and United Kingdom (R2 = 0.60) and between the rotavirus IQS and acute gastroenteritis hospitalizations in the United States (R2 = 0.87) and Mexico (R2 = 0.69) (P < .0001 for all correlations). The correlations were stronger in the prevaccine period than in the postvaccine period. After vaccine introduction, the mean rotavirus IQS decreased by 40% (95% confidence interval [CI], 25%-55%) in the United States and by 70% (95% CI, 55%-86%) in Mexico. In the United Kingdom, there was a loss of seasonal variation after vaccine introduction.
  
  
  CONCLUSIONS
  Rotavirus internet search data trends mirrored national rotavirus laboratory trends in the United States and United Kingdom and gastroenteritis-hospitalization data in the United States and Mexico; lower correlations were found after rotavirus vaccine introduction.
authors.affiliation: Division of Viral Diseases, National Center for Immunizations and Respiratory Diseases, Atlanta, Georgia.|Epidemic Intelligence Service, Office of Public Health Scientific Services, Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Minesh P
authors.initials: MP
authors.lastname: Shah
authors.affiliation: Division of Viral Diseases, National Center for Immunizations and Respiratory Diseases, Atlanta, Georgia.
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Lopman
authors.affiliation: Division of Viral Diseases, National Center for Immunizations and Respiratory Diseases, Atlanta, Georgia.
authors.forename: Jacqueline E
authors.initials: JE
authors.lastname: Tate
authors.affiliation: National Institute for Health Research, Health Protection Research Unit GI Infections, University of Liverpool, Liverpool, England.
authors.forename: John
authors.initials: J
authors.lastname: Harris
authors.affiliation: National Center for Child and Adolescent Health, Ministry of Health, Faculty of Medicine, National Autonomous University of Mexico, Mexico City, Mexico.
authors.forename: Marcelino
authors.initials: M
authors.lastname: Esparza-Aguilar
authors.affiliation: Ministry of Health, State of Morelos, Cuernavaca, Mexico.
authors.forename: Edgar
authors.initials: E
authors.lastname: Sanchez-Uribe
authors.affiliation: Ministry of Health, State of Morelos, Cuernavaca, Mexico.
authors.forename: Vesta
authors.initials: V
authors.lastname: Richardson
authors.affiliation: Center for Delivery, Organization and Markets, Agency for Healthcare Research and Quality, Rockville, Maryland.
authors.forename: Claudia A
authors.initials: CA
authors.lastname: Steiner
authors.affiliation: Division of Viral Diseases, National Center for Immunizations and Respiratory Diseases, Atlanta, Georgia.
authors.forename: Umesh D
authors.initials: UD
authors.lastname: Parashar
mesh_terms: D002675:Child, Preschool; D005759:Gastroenteritis / Q000453:epidemiology; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D057226:Information Seeking Behavior; D020407:Internet / Q000706:statistics & numerical data*; D008800:Mexico / Q000453:epidemiology; D012400:Rotavirus Infections / Q000453:epidemiology* / Q000517:prevention & control; D022243:Rotavirus Vaccines / Q000627:therapeutic use*; D012621:Seasons; D006113:United Kingdom / Q000453:epidemiology; D014481:United States / Q000453:epidemiology
chemical_list: D022243:Rotavirus Vaccines