Knowledge, attitudes, and practices toward hepatitis B virus infection among hepatitis-B patients in Qinghai Province, China.

Electronic cigarettes (e-cigarettes) are the most commonly used tobacco products in US middle and high school students, according to the 2024 National Youth Tobacco Survey []. The prevalence of current e-cigarette use (vaping) is 7.8% among high school students and 3.5% among middle school students in 2024 []. Although the long-term health effects of vaping are largely unknown, experimental and clinical studies have reported the acute health effects of vaping, including toxicity in the respiratory and cardiovascular systems []. Epidemiology studies associated vaping with respiratory disorders, such as wheezing, asthma, and chronic obstructive pulmonary disease, and mental health issues [–]. Regulatory policies for e-cigarettes vary across countries. In 2009, the U.S. began regulating e-cigarettes as tobacco products, and in 2016, the US Food and Drug Administration (FDA) expanded its authority to regulate e-cigarettes as tobacco products []. In 2020, to prevent youth access to flavored e-cigarettes, the US FDA implemented a flavor enforcement policy to restrict the sale of all unauthorized flavored cartridge-based e-cigarettes other than tobacco and menthol flavors []. On June 23, 2022, the US FDA issued marketing denial orders (MDOs) to all JUUL products in the US, which prohibits the company selling and distributing these products in the US market []. While the JUUL products were dominant in the US e-cigarette market in 2018 and 2019 [], these MDOs can lead to active online discussion around the policy change as well as the e-cigarettes. The e-cigarette products in Canada have a nicotine concentration cap of 20 mg/ml, with federal laws restricting their advertising, mandating plain packaging, and prohibiting their sales to minors []. In the UK, e-cigarettes are regulated as a less harmful smoking cessation tool with restrictions on nicotine strength (20 mg/ml), tank capacity (2 ml), and advertisement []. Australia has the world’s strictest e-cigarette policies, with e-cigarettes classified as prescription-only medicines in 2021 and announced plans in 2023 to ban disposable vapes and restrict flavors to curb youth uptake of e-cigarettes []. Regulatory policies on e-cigarettes can have a significant impact on the perception and prevalence of e-cigarette use. For example, the UK government’ 2024 vaping policy announcement exacerbated negative harm perceptions of e-cigarettes []. Furthermore, cross-national differences in e-cigarette regulatory policies may shape public perceptions and influence the prevalence and patterns of e-cigarette use. With the continuing battle between tobacco regulatory policies and aggressive industry marketing, monitoring public discussion of e-cigarettes is critical, as they may directly influence the prevalence of e-cigarette use. Risk perception theory suggests that individuals’ behaviors are influenced not only by objective risk but also by subjective perceptions of harm and benefit []. Therefore, it is critical to monitor public discourse of e-cigarettes over time. Tobacco regulatory policies or measures, such as the announcement of e-cigarette flavor ban locally or nationally, can influence public discussions and online sentiments towards e-cigarettes by signaling potential health risks [, –]. Conversely, industry marketing strategies can reshape public discussions by promoting favorable attitudes toward e-cigarette use [–]. Media framing theory highlights how the presentation of information, such as tobacco regulatory policy announcements or product marketing, can influence public discussion and sentiment []. Twitter (now X) provides a valuable real-time lens into public discourse since Twitter posts capture immediate public responses to both tobacco regulatory policies (e.g., e-cigarette flavor ban announcements) and industry marketing activities (e.g., e-cigarette promotion by influencers). Therefore, Twitter data have been extensively used to examine online discussions of e-cigarettes, as well as how regulatory policies influence these discussions [–, , ]. Previous studies showed that Twitter users’ sentiments toward e-cigarettes became significantly more negative following announcements by New York State and the US FDA regarding bans on the sale of flavored e-cigarettes, excluding menthol and tobacco flavors [, ]. Subsequent work further evaluated the impact of New York State’s comprehensive flavor ban—which prohibits the sale of all flavored vapor products except tobacco and other authorized flavors—and found increased prevalence of discussions related to youth, nicotine products, and quitting behaviors using Twitter data from February to November 2020 []. Furthermore, one study reported that discussions surrounding vaping cessation became more prominent following the FDA’s announcement and implementation of the flavor enforcement policy []. Beyond the U.S. context, one prior study leveraged Twitter data to examine public discussions of e-cigarette prescription policies