Teen Vaping: Not Gone, But Forgotten

Since their introduction to the United States market in 2007, electronic cigarettes have gained popularity in use, specifically in the youth and young adult population.¹ By 2014, e-cigarettes became the most popular choice of tobacco products among adolescents. Between 2011 to 2018, e-cigarette use in high school students rose from 1.5% to 20.8%; use in middle school students also rose from 0.6% to 4.9% over the same period.² Historically, the appeal of vaping products, specifically in youth and young adult populations, has been attributed to several factors such as its discreet delivery system shaped like USB flash drives, high nicotine content and multiple flavors options.^2,3 Another draw to vaping has been the idea that vaping is less harmful than tobacco cigarettes. This has been supported by many scientists for reasons such as the far greater number of chemicals in cigarettes, data that supports that lung function improves when cigarettes are replaced with e-cigarettes and studies that show higher inflammatory biomarkers in cigarette users than vape users.⁴ Vaping has also been studied as a successful method for smoking cessation. ^4,5 It is important to note, however, that even those that have concluded that vaping is less harmful, acknowledge that vaping is not without its health risks.

The harm associated with e-cigarettes or vaping products was not fully appreciated until 2019 when the Center for Disease Control (CDC) first reported a severe pulmonary illness associated with its use. Cases of e-cigarette, or vaping, product use associated lung injury (EVALI) were tracked by the CDC after it was identified. Given the alarming number of cases reported, the CDC officially declared it an epidemic in 2019. The peak number of cases reported were 215 between August 2019 and September 2019.⁶ In February 2020, the CDC discontinued its monitoring of cases which coincided with the start of the COVID-19 global pandemic. Despite this, the attention by public health experts on EVALI prompted a harder look at vaping usage and efforts to regulate vaping products.¹

A diagnosis of exclusion, EVALI has no specific clinical features or symptoms; there has been several proposed definitions but the most widely accepted tool for identification has been based on the CDC definition of confirmed cases which includes: 1) e-cigarette use in 90 days before symptom onset; 2) pulmonary infiltrates on plain film chest radiography or ground glass opacities on chest computed tomography; 3) absence of pulmonary infection on initial work up; and 4) no evidence of alternative diagnosis.¹

The pathogenesis of EVALI is not fully understood but a study published in 2019 identified vitamin E acetate (VEA) in the bronchoalveolar fluid of 48 out of 51 EVALI patients.⁷ This supported previous observations that a majority of EVALI patients reported use of tetrahydrocannabinol (THC) containing products and VEA has frequently been used in these products to thicken the liquid.⁸ Subsequent studies in both in vitro and in vivo models also observed cytotoxicity, barrier dysfunction and inflammation to lung tissue that was exposed to aerosolized VEA, as well as other chemical components commonly found in THC containing products.³ Despite the strong evidence that supports a causal link between VEA and

EVALI, other contributing factors are being explored, particularly for nicotine only e-cigarettes that do not contain VEA like cannabinoid e-cigarettes do. EVALI has prompted responses by public health agencies on both a federal and state level. The US Food and Drug Administration (FDA) began having authority over e-cigarettes and vaping products in 2016 under the Deeming Rule section of the Tobacco Control Act.⁹ This rule broadened the FDA’s authority to regulate manufacturing of vaping products, requiring manufacturers to submit applications for approval of products to the FDA.⁹ This led to several significant changes including the ban on selling vaping products to youth under the age of 21, effective removal of VEA in some vaping liquid products, and restriction of sales on unauthorized flavored cartridge-based e-cigarettes.

In 2020, the Prevent All Cigarette Trafficking Act (PACT Act), a legislative bill regulating the delivery and sales of tobacco products, was amended to include e-cigarette and vaping products, thus attempting to control access for young adults to vaping products and complementing the regulations of the Tobacco Control Act.¹⁰ State level regulations have also attempted to fill gaps in addressing the use of e-cigarettes by either enacting special taxes on e-cigarettes, requiring special licenses for retail distributors and/or restricting product packaging.^11,12 Some states such as Colorado, Massachusetts, New Jersey and California have also banned specific flavors to make vaping less appealing to young populations.¹¹

In Missouri, restrictions for vaping have largely mirrored those of other states including the regulations for licensing, packaging, and distribution.¹³ More recently, Missouri has introduced legislation to modify the existing Clean Indoor Air Act to ban vaping and marijuana in all indoor public spaces.¹⁴ One study analyzed e-cigarette use and its association with different types of state regulations; these results suggest a decline in e-cigarette use and initiation in states that enacted laws regulating the distribution and licensing of vaping products.¹¹ The results are promising in the battle against EVALI.

In addition to federal and state regulations on vaping products themselves, several health campaigns have been launched to educate youth and young adult populations to discourage the use of vaping products. Campaigns such as The Truth Initiative and the FDA’s Real Cost campaign were originally launched to spread awareness of tobacco use but have since evolved to include e-cigarettes/vaping in their educational focus for young adults. A randomized controlled trial performed in 2021 examined the impact the Real Cost Campaign had on discouraging vaping use and the results showed a lower usage of vaping in adolescents who were shown anti-vaping advertisements three times weekly as compared to the control group.¹⁵ Studies such as this show that public health campaigns can have a large impact on disease prevention like EVALI. At the height of EVALI cases, 20% (5.4 million) of high school and middle school students reported e-cigarette use, by far the most common method of using tobacco products; in comparison, 4.3% (1.2 million) students reported using cigarettes.¹⁶ As recent as 2024, the National Youth Tobacco Survey stated that 5.9% (1.63 million) middle and high school students reported using e-cigarettes and 1.8% students reported using cigarettes; this is the lowest documented use ever obtained by the National Youth Tobacco Survey (Figure 1).^17,18

Figure 1.

Percentage of United States high school students who report use of any tobacco product, e-cigarettes or marijuana use in the past 30 days from 2020-2024¹⁷,²²

Although tobacco is commonly delivered via e-cigarette or vaping systems, nearly one in three students reported using vaping products to deliver marijuana as well (Figure 1).^17,18 The prevalence of cannabis, in general, has been on the rise in the US. In 2022, 15.1% of adults reported using marijuana, an increase from 13.1% in 2021.¹⁹ Approximately one-fourth of these patients reported vaping as the most popular delivery method.¹⁹ Legalization of marijuana has likely contributed to the rise in popularity. A 2023 study surveying over 5,000 Missouri college students across 25 campuses showed a 66.23% increase in use of marijuana between 2013–2023; after legalization in 2023, 10% of cannabis naïve students reported intent to use and 22% of current cannabis users reported intent to increase use.²⁰ Thus far, most EVALI cases have been reported in patients whose primary use of vaping was for marijuana, so these distinctions are important to track.

The fall in EVALI cases is likely due to multiple factors. Although new public health policies increased awareness and better regulatory measures have contributed to its decline, it is likely that the condition has been under recognized. Prior to the 2019 epidemic, studies of the adverse health effects linked to e-cigarettes first emerged in 2012.³ In 2014, an acute respiratory condition was described in a case report possibly linking it to e-cigarettes.³ More cases followed, ultimately leading to the official declaration of the epidemic in September 2019. After discontinuation of monitoring by the CDC, some states chose to continue tracking cases; however, to date there is no official report for the number of EVALI cases since monitoring was stopped in February 2020. The American Thoracic Society in its 2022 workshop report on EVALI noted that although there was useful data obtained during the tracking period of EVALI, this was captured over a period of less than 1 year.¹ Since discussion on EVALI has dulled over the past few years, there is also a component of poor awareness by physicians thereby making it possible that the diagnosis is missed. It begs the question, are EVALI cases truly dropping at the rate we have seen or are patients being misdiagnosed?

A diagnosis of EVALI poses a large challenge for physicians. As previously mentioned, the nonspecific findings and long differential can lead physicians down many different paths, so a thorough exposure history is key. While conversations on tobacco cessation have become a standardized part of practice, vaping has only joined the discussion in the past few years. Guidelines, such as those from the American College of Cardiology, have outlined a systematic approach to counsel patient through smoking cessation but vaping has yet to receive the same attention.²¹ In fact, studies such as those from Hajek et al. has demonstrated higher success in smoking cessation with the use of e-cigarette products over traditional nicotine replacement therapy (NRT) with the caveat being a high rate of continued usage of e-cigarettes at 52 weeks compared to NRT participants.⁵ Studies such as these have acknowledged the theoretical health consequences of e-cigarette use itself, so these outcomes should not be considered as an acceptable alternative to the harms of traditional smoking. Therefore, physicians should approach the conversation of vaping usage under the same umbrella of tobacco cessation given what we have learned thus far from the EVALI epidemic.

Although there has been promising strides forward in the education and prevention of EVALI, there is still much to be done. Proposed actions to continue efforts focuses on two major aspects: prevention of vaping by the public and better medical understanding of the condition. For the former, more standardized, federal regulations of e-cigarette distribution and manufacturing should be pursued as it has already been shown to have a positive effect. Limiting flavor options to make vaping less appealing, continued education on health harms, and restricting access to products are cornerstones of this approach.¹ In matters of the study on EVALI itself, a standardized coding system and national case registry should be established to identify cases.¹ In doing so, data could be used to further explore the pathogenesis of the condition and eventually guide treatment management. Physicians should continue to take careful history of vaping use when evaluating patients with acute respiratory distress and consider EVALI in their differential. In the spirit of prevention, they should also encourage and counsel cessation of vaping with the same discrimination that cigarette use has received.