Table 3. Characteristics of 15 influenza-like illness studies addressing research question 1 ^a .

Author (et al.)	Social Media Type	Location	Sample Population	Study Type	Population/Disease Studied	Time Period	Intervention/Exploratory
Achrekar [ 16 ]	Twitter	North America	1.9 million Twitter users	Retrospective	Influenza	Not specified	Exploratory
Aramaki [ 40 ]	Twitter	Asia	300 million tweets	Retrospective	Influenza (H1N1)	2008–2010	Exploratory
Chew [ 47]	Twitter	North America	Over 2 million tweets	Retrospective	Influenza	May–Dec 2009	Exploratory
Collier [ 44 ]	Twitter	Asia/Europe	5283 tweets	Retrospective	Influenza	2010	Exploratory
Corley [ 18 ]	Blogs, forums	North America	158,497,700 English language	Retrospective	Influenza	2008–2009	Exploratory
Culotta [ 17 ]	Twitter	North America	574,643 tweets	Retrospective	Influenza	Feb–Apr 2010	Exploratory
Culotta [ 43 ]	Twitter	North America	500 million tweets	Other	Influenza	2009/10 flu season	Exploratory
De Quincey [ 45 ]	Twitter	Europe	135,000 tweets	Retrospective	Influenza	2009	Exploratory
Doan [ 33 ]	Twitter	Europe (UK)	24.5 million Twitter Users	Retrospective	Influenza	2009–2010	Exploratory
Ishikawa [ 38 ]	Twitter	Asia (Japan)	157,007 tweets	Prospective cohort	Influenza	July 2011– Jan 2012	Exploratory
Lampos [ 31 ]	Twitter	Europe (England & Wales)	200,000 geolocated tweets; Urban centers	Correlation study	Influenza	2009/10 flu season	Exploratory
Okamura [ 39 ]	Twitter	Asia (Japan)	716,417 tweets	Retrospective	Influenza	Dec 2010– Jan 2011	Exploratory
Sadilek [ 15 ]	Twitter	North America (NYC area)	6237 tweets	Prospective cohort	Influenza	2010	Exploratory
Signorini [ 19 ]	Twitter	North America	Twitter users	Retrospective	Influenza (H1N1)	2009	Exploratory
Szomszor [ 32 ]	Twitter	Europe	3 million tweets	Retrospective	Influenza (H1N1)	May–Dec 2009	Exploratory

^aQ1: Can social media be integrated into disease surveillance practice and outbreak detection management to support and improve public health and outbreak management?