1 Reporting on scientific studies in newspaper articles on COVID-19 in Italy and the US: missing citations and information bubbles Francesca Palatta 1 , Arthur Cassa Macedo 2 , Flavia Marcacci 1 , Alessandro Martinisi 3,4 , Daniella de Freitas Pereira Angelo Durço 5 , Roberto Calheiros Barros Neto 6 , Pietro Ghezzi 7* 1 Pontifical Lateran University, Rome, Italy 2 Department of Neurology and Neurosurgery, McGill University, Montreal, Canada 3 Kaunas University of Technology – KTU, Faculty of Social Sciences, Arts and Humanities, Kaunas, Lithuania; 4 Franklin University Switzerland, Sorengo (Lugano), Switzerland 5 Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil 6 Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil 7 Department of Biomolecular Sciences, University of Urbino, Urbino, Italy *Corresponding author. E-mail: pietro.ghezzi@gmail.com Abstract Newspapers are a major source of health information, including on COVID-19. Many news articles are based on press releases describing research published in scientific journals. We studied a sample of articles in US and Italian newspapers for their mention of non-pharmacological interventions (face masks and lockdown) and pharmacological ones, both effective and ineffective (convalescent plasma, hydroxychloroquine, ivermectin, vaccines and vitamin D), and whether these were mentioned in a favorable or unfavorable way. We checked for the presence or absence of explicit mentions or links of the primary source of scientific information. Finally, we analyzed whether there was a trend to form “information bubbles” where some opinions around different treatments cluster together. Of 480,819 news in the USA and 767,172 in Italy, vaccines, face masks and lockdown were the most mentioned interventions. Of the pharmacological interventions other than vaccines, ivermectin and hydroxychloroquine were more frequently mentioned in the USA than in Italy (5- and 6-fold, respectively) although, when analyzing a sample of 210 news returned from a search on COVID-19 mentioning a research publication, articles from the USA were less favorable than