Content and User Engagement of Health-Related Behavior Tweets Posted by Mass Media Outlets From Spain and the United States Early in the COVID-19 Pandemic: Observational Infodemiology Study

Miguel Angel Alvarez-Mon   ^{1, 2, 3} , MD, PhD ;   Victor Pereira-Sanchez   ⁴ , MD, PhD ;   Elizabeth R Hooker   ^{5, 6} , MPH, MS ;   Facundo Sanchez   ^{7, 8} , MD ;   Melchor Alvarez-Mon   ^{1, 3} , MD, PhD ;   Alan R Teo   ^{5, 9} , MS, MD

¹ Department of Medicine and Medical Specialties, Faculty of Medicine and Health Sciences, University of Alcala, Alcala de Henares, Spain

² Department of Psychiatry and Mental Health, University Hospital Infanta Leonor, Madrid, Spain

³ Ramón y Cajal Institute of Sanitary Research (IRYCIS), Madrid, Spain

⁴ Department of Child and Adolescent Psychiatry, NYU Grossman School of Medicine, New York, NY, United States

⁵ VA Portland Health Care System, Health Services Research & Development Center to Improve Veteran Involvement in Care, Portland, OR, United States

⁶ OHSU-PSU School of Public Health, Oregon Health and Science University, Portland, OR, United States

⁷ Lincoln Medical and Mental Health Center, New York, NY, United States

⁸ Devers Eye Institute, Portland, OR, United States

⁹ Department of Psychiatry, Oregon Health & Science University, Portland, OR, United States