Provide critical analysis a balanced discussion of the strengths and weaknesses of the research, based on your appraisal and supported with specific examples from the study

a) Introduction: broad analysis of the study introduction

Introduction

Social media has been widely used in health contexts by various users. For individuals, social media is a primary source of COVID-19 information for patients [1]. Social media is used by 80% of cancer patients to connect with peers [2]. For health organizations, more than 80% of US state health departments have social media accounts [3]. Among health professionals, 65% of radiologists across the United States and Europe use social media for various health-related reasons [4]. A review of the state of the art can provide guidance for practitioners who intend to use social media and for researchers who intend to advance our understanding of social media use for health purposes.

Before reviewing social media use for health purposes, it is necessary to outline the scope of social media and health purposes. Social media has been defined in different ways. Some definitions focus on the technological features of social media that distinguish it from traditional technologies. For example, Kaplan and Haenlein [5] emphasized that social media is a type of application based on the internet and web 2.0 technology. Other definitions focus on the communication features of social media that distinguish it from traditional media. For example, McGowan et al [6] defined social media as an online environment where users can contribute to the content and consume content mostly generated by other users. They also emphasized that content being created by users for users is an important feature that distinguishes social media from traditional media [6]. From a communication perspective, this paper emphasizes the communication features of social media and considers social media as a web 2.0based platform for individuals to get access to, share, and generate content. Health purposes include health-related goals such as health promotion, medical service and administration, health research, medical education and training, and health-related social movements. This review focuses on users purposively getting access to, sharing, and generating content on social media in order to achieve various health purposes.

Previous reviews about social media use for health mostly focused on using social media for a single health purpose. These reviews summarized social media as a tool for health interventions [7], health campaigns [8], medical education [9], disease outbreak surveillance [10], and health promotion and behavior change [11]. The most recent comprehensive review of social media use for various health-related purposes was conducted by Moorhead et al [12] and included studies published between 2002 and 2012. However, multiple new uses have emerged between 2013 and 2020 given the rapid development of social media and the need for effective communication and infodemiology practice in the face of emerging health risks. Following Moorhead et al [12], this study reviewed articles published between 2006 and 2020 and categorized social media uses for health purposes in terms of user types, namely, health institutions, health researchers and professionals, and the public. By conducting a systematic review, we aimed to summarize social media use for health purposes, identify new uses that have emerged since 2013 as compared with Moorhead et al [12], and discuss research gaps and future directions for research in social media use for health purposes.