Amid the many controversies about vaping’s health effects, there’s one thing public health experts agree on: E-cigarettes are less harmful than regular cigarettes. Tobacco kills up to half of its users, which is why cigarettes are considered the deadliest consumer product ever introduced to the market. Even with the uncertainty about vaping’s long-term risks, researchers have found that vapers are exposed to fewer toxins and carcinogens than cigarette smokers.

The public, meanwhile, seems increasingly confused.

The number of people who think e-cigarettes pose a similar danger to conventional cigarettes is rising in the US, according to a new survey published this week in JAMA. It found that the percentage of adults who said e-cigarettes are less harmful than combustible cigarettes dropped from 29 percent to 26 percent between 2017 and 2018. Meanwhile, the percentage who believe e-cigarettes are as harmful as cigarettes increased, from 36 percent to 43 percent, in the same period.

There was also a rise in the number who believe vaping is more harmful or much more harmful than smoking, from 2 percent to 4 percent between 2017 and 2018.

The trend held even among current and former smokers — a group that might benefit from switching to vaping. That’s concerning, said Amy Nyman, lead author of the study and research associate in the School of Public Health at Georgia State University, in a statement. “Smokers who perceive too much risk from e-cigarettes may decide against using them to quit smoking and may instead continue with their combustible smoking habit.”

“Smoking itself is literally the most harmful thing anyone can do,” Michael Eriksen, a co-author on the paper and the founding dean of the School of Public Health at Georgia State, told Vox. “For the public to equate [e-cigarettes and cigarettes] and see [vaping] as more harmful than smoking is really surprising.”

This survey data was collected before the outbreak of vaping-related lung disease, which, as of November 20, has sickened more than 2,000 people and killed 47 across the US. Though cases in the outbreak have now mostly been linked to THC vape products, “If this survey were to be done again, it would probably be shocking in terms of even more negative perceptions,” Eriksen added.

How the public health message about vaping became so muddled

Now, the question is: Why is the e-cigarette public health message so muddled? The researchers had a few ideas about that.

Risk communication is notoriously fraught. People have an especially hard time differentiating between absolute risk and relative risk. (Relative risk looks at the odds of something happening compared to something else — like diseases arising from smoking compared to vaping. Absolute risk looks at the odds of something happening at all over a period of time — such as a smoker’s long-term chances of developing cancer.) “We in public health don’t do a good job in communicating this,” Eriksen said.

People have an especially hard time differentiating between absolute risk and relative risk. (Relative risk looks at the odds of something happening compared to something else — like diseases arising from smoking compared to vaping. Absolute risk looks at the odds of something happening at all over a period of time — such as a smoker’s long-term chances of developing cancer.) “We in public health don’t do a good job in communicating this,” Eriksen said. It doesn’t help that media and policy discussions around vaping aren’t very nuanced. Over the last couple of years, stories have abounded about vaping’s acute health risks — such as exploding e-cigarette cartridges or “popcorn lung,” a dangerous condition that was first seen in workers exposed to chemicals involved in the manufacturing of microwave popcorn.

Separately, the regulatory discussion around vaping has centered on banning certain e-cigarette products, or as the American Medical Association recommended this week, banning vaping products all together, “with the exception of those approved by the FDA for tobacco cessation purposes and made available by prescription only.” In these stories — about severe short-term risks and crackdowns — accurate public health messages about the long-term benefits of e-cigarettes for smokers, for example, can easily get lost.

There are still no FDA-approved vape devices for quitting smoking cessation, so the public health community has mostly been silent. In the UK, e-cigarettes are treated like a medicine and available to help people quit smoking. “We [in public health] don’t communicate that message here because e-cigarettes are not approved as [smoking] cessation devices,” Eriksen explained. “So there’s this void of information.” That’s meant smokers who want to use vapes to quit are left to navigate the system by themselves, seeking advice from their doctors, friends, or even local vape shops. It’s also meant there’s not much out there to counter the sometimes erroneous marketing from e-cigarette manufacturers. And this haphazard approach is not a great starting point for accurate public health messaging.

Ideally, the public would understand that non-tobacco users should never vape. Vaping, while safer than smoking, carries health risks and the long-term harms still aren’t known. “These products are not safe. They are harmful. If you’re not a user currently you should never use them,” Eriksen said.

There’s a second message for smokers: they might consider switching to vaping to reduce their risk of tobacco-related disease. Again, that’s because of the overwhelming evidence that vaping is safer than smoking. For example, a National Academies of Sciences, Engineering, and Medicine 2018 report on e-cigarettes analyzed the findings of 800 peer-reviewed studies. “There is conclusive evidence,” the report stated, “that completely substituting e-cigarettes for combustible tobacco cigarettes reduces users’ exposure to numerous toxicants and carcinogens present in combustible tobacco cigarettes.”