EVALI outbreak reshaped public perceptions of e-cigarette harm

Cigarettes are one of the deadliest products on the market – but the risks of alternatives are not always clearly understood. That disconnect came into sharp focus in 2019, when headlines warned of a mysterious and sometimes deadly lung illness linked to vaping, sending patients to the hospital with severe breathing problems. The coverage fueled widespread concern, and many smokers began to mistakenly view e-cigarettes as just as or more dangerous than traditional cigarettes.

New research from MUSC Hollings Cancer Center, published in Addictive Behaviors, suggests that this perception still lingers, shaping how people think about e-cigarette risk today. Drawing on data from a nationwide clinical trial, MUSC researchers led by Tracy Smith, Ph.D., found that during and after the outbreak – known as e-cigarette or vaping product use-associated lung injury, or EVALI – perceptions of e-cigarette risk rose sharply and remained elevated.

"That period really changed how people think about these products," Smith said. "Even after we learned more about what caused the illness, those perceptions didn't fully reset."

A moving target: How risk is understood

E-cigarettes and traditional cigarettes are both tobacco products, and both carry risks. But they are not equally harmful.

The U.S. Food and Drug Administration recognizes what researchers call a "continuum of risk," with combustible cigarettes at the highest end because they expose users to far more toxic chemicals and carcinogens.

Still, many Americans do not see it that way. Over time, more people have come to believe that e-cigarettes are just as or even more harmful than cigarettes.

Smith and her colleagues, including trainees at multiple levels, sought to understand those risk perceptions. The study was led by Emily Barros, a trainee in the MUSC College of Medicine's Drug Abuse Research Training (DART) Summer Fellowship program, with contributions from Iyonica Ravenel, a high school student in the SC CHEER Youth Enjoy Science (YES) program.

They turned to data from a nationwide randomized clinical trial of more than 600 adult smokers conducted between 2018 and 2022. Led by Hollings researcher Matthew Carpenter, Ph.D., that larger study found that participants given e-cigarettes smoked fewer cigarettes and were more likely to quit compared with those given traditional cigarettes – suggesting that e-cigarettes may influence smoking behavior for some people.

Because the study enrolled participants before, during and after the EVALI outbreak, it offered a rare opportunity to track how risk perceptions changed in real time.

In the current study, participants were asked to rate two questions on a scale from 0 to 10:

1. How harmful do you consider cigarette smoking to you personally?
2. How harmful do you consider e-cigarettes to you personally?

By comparing those answers, the researchers could measure relative risk perception, which refers to how people weigh one product against another.

The EVALI effect

During the EVALI outbreak and in the years that followed, participants viewed e-cigarettes as significantly riskier compared with cigarettes than they had before the outbreak.

That shift persisted even after scientists identified the cause: vitamin E acetate, an additive found primarily in illicit THC vaping products, not standard nicotine e-cigarettes.

"The information that came out later didn't reach everyone," Smith said. "Or at least it didn't have the same impact as the initial coverage."

In other words, the first impression stuck.

Notably, this shift in perception was not evenly distributed. Risk perceptions increased significantly during and after EVALI for non-white participants but did not change meaningfully for white participants. That matters, Smith said, because those same populations already bear a disproportionate burden of tobacco-related disease.

"If people believe that e-cigarettes are just as harmful as cigarettes, they may be less likely to switch," she said. "That could unintentionally reinforce existing health disparities."

A complicated message for public health

None of this means e-cigarettes should be seen as safe.

They carry risks, including nicotine dependence, and their long-term health effects are still being studied. For young people or anyone who does not smoke, the guidance continues to be to avoid smoking altogether.

But for adults who already smoke – a group for whom cigarettes remain the leading cause of preventable death – the conversation is more nuanced.

The stakes are especially high for cancer. One in three cancer deaths in the U.S. is linked to smoking, and quitting can improve treatment outcomes and survival rates.

At Hollings, patients can access support through a Tobacco Treatment Program, which offers counseling, medication and personalized plans to help people to quit. Hollings also offers a Lung Cancer Screening Program for those at high risk, providing an opportunity for early detection.

Still, quitting is difficult, and many people are not successful on their first attempts, even with approved medications. In those cases, Smith said, it is critical that patients and clinicians have honest and open discussions about alternatives and their relative risks.

For some patients, that may include e-cigarettes – but with a clear goal.

"The greatest benefits come from quitting smoking altogether. If someone is going to use e-cigarettes to quit smoking, the goal has to be to switch completely," she said. "Because continuing to smoke at the same level while vaping doesn't reduce risk."

The study also points to a broader challenge for public health: Risk is shaped not only by evidence but by how that evidence is communicated. During EVALI, media coverage often failed to distinguish between nicotine e-cigarettes and THC products – even though most cases were ultimately traced to the latter.

That gap, researchers say, may have contributed to lasting misunderstandings.

"There are real risks with e-cigarettes," Smith said. "But it's important to communicate clearly about how those risks compare, especially for people who are currently smoking."

For clinicians, that means tailoring conversations – discouraging use among nonsmokers while helping smokers to navigate quitting. Researchers, meanwhile, are left to keep tracking how perceptions influence smoking behavior. Because how people perceive risk can shape real health decisions, including whether to keep smoking or consider quitting.