Read: Contesting the science of smoking

At the moment, the leading public-health issue in the news is vaping. Push alerts mark incremental tallies in people hospitalized with serious respiratory illnesses related to vaping. So far this year the number is 805—with a median age of 23—according to a widely discussed report released by the Centers for Disease Control and Prevention last week. The week prior, 530 hospitalizations had been reported. The number of deaths related to vaping has grown to 12.

In September, President Donald Trump announced a commitment to ending the vaping scourge: “We can’t allow people to get sick, and we can’t have our youth be so affected.” In addition to the youth of the victims, uncertainty about exactly what’s causing this spike in sickness has fueled an emotional public response. A mix of political momentum and genuine will to protect kids has led to calls for bans and absolute avoidance of vapes. Massachusetts temporarily banned the sale of all vaping products. Walmart announced it would stop selling all vaping products. California allocated $20 million for a “vaping-awareness campaign.”

There appears to be a unanimous consensus that something should be done to better understand and prevent this vaping-related harm. The message from many in the public-health community simply has been to avoid vaping. Last week the CDC told Americans as much. But as bans are actually being implemented, some experts are realizing the potentially dangerous effects of misplacing collective anxiety.

“What we’ve seen in the past several months is unique,” says Brian King, the CDC’s deputy director for research translation on smoking and health. After the recent, jarring uptick in serious cases of vaping-related lung illness, he has been trying to discern the exact extent of the harm. He believes that the agency is close to having a full accounting. “It’s possible there is an influence of stories in the media—that people may be more likely to report or to suspect vaping was the cause of lung disease,” King says. “Even so, the rates are markedly higher than in past years, so it’s likely something new is going on.”

Read: Vaping’s plausible deniability is going up in smoke

Abigail Friedman, who studies tobacco use at the Yale School of Public Health, points out that the majority of the most popular vaping products have been on the market for at least a few years. The question is not whether vaping itself is safe or unsafe, she emphasizes, but what elements of the practice are causing these acute diseases: “An e-cigarette is fundamentally a device, not a substance. One thing that I think is really confusing people is that vaping just means using an e-cigarette. It doesn’t tell you what people put in it. You could put water in an e-cigarette, right?”

Vaping water should be a harmless, if curious, thing to do. Adding nicotine to that vapor, on the other hand, noticeably affects the cardiovascular system and brain. The addictive properties of nicotine can alter neural functioning permanently, especially in younger people—that’s why every medical institution advises against vaping. But nicotine alone should not acutely cause the sort of severe inflammatory lung disease that is being seen.