If you keep up with health news, chances are you've heard about the mysterious "vaping disease" about, oh, a million times this fall. Here at Sciencing, we've reported on it a few times: once in August, when the outbreak started, and in September, as scientists were desperately trying to figure out the cause.

And there's a reason it's such a big story. For one, vaping has long had the reputation for being a healthier alternative to smoking. While vapor does admittedly have fewer chemicals than actual smoke, the explosion in vaping illness proves it's not healthy.

There's also the element of mystery surrounding the disease. For months, scientists weren't sure what exact chemicals in vapes were causing the disease. Even those with healthy lungs were affected. And some people with vaping disease looked like they'd experienced chemical burns – completely unlike what you'd expect to see from long-term smokers.

What's more, vaping illness may be a particular threat to teens. While smoking among teens went down between 2011 and 2016, according to the Centers for Disease Control and Prevention, vaping has been on the rise. E-cigarette use by middle school and high school students jumped 4.5 percentage points from 2018 to 2019, according to research published in the New England Journal of Medicine.

Finally, it's a big story because, well, it has affected tons of people. As of Nov. 7, the CDC reports that vaping disease has impacted more than 2,000 people across the United States, and it's killed almost 40 people.

So, clearly, it's a big story. And, thankfully, scientists have just made a breakthrough in understanding what causes vaping illness. Here's what we know so far, and the next steps to solving the crisis.

Scientists were flummoxed in the weeks after the vaping illness outbreak, because there seemed to be little pattern between victims. Some reported vaping THC, the active ingredient in cannabis, while others said they vaped nicotine only. Some victims had conditions that might predispose them to problems with vaping like asthma – while others were completely healthy.

Well, researchers at the CDC have found one potential cause: vitamin E acetate, an ingredient sometimes added to vape cartridges. Vitamin E can work as a preservative in vape products, and it's also used to dilute THC oil in some vaporizer cartridges.

It seems like an unlikely culprit, right? After all, vitamin E is generally good for you. It's an antioxidant and an essential vitamin, which means your body needs it to function. And it's found in plenty of harmless products, like skincare.

Unfortunately, while ingesting or applying vitamin E to your skin may be safe, inhaling it isn't.

The researchers identified vitamin E acetate as a chemical of concern by looking at lung fluid samples obtained from 10 patients with vaping disease. While each patient had a unique range of chemicals in their lung fluid – hinting that they'd all used slightly different vaping products – they all contained vitamin E acetate. That helped researchers pinpoint vitamin E acetate as a likely contributor to vaping illness.

Researchers at the CDC have described their discovery as a "breakthrough" in understanding vaping illness, but we've still got a long way to go. For one thing, we still aren't sure exactly how vitamin E acetate affects our lungs.

Since it's added to vape products as a thickening agent, it's possible that the thicker oil simply stays within your lungs for longer, causing irritation – kind of like how an oil spill sticks to bird feathers, except it's happening in your lungs.

But, at this point it's still a guessing game. Researchers at the CDC are working hard to expand on their results to better understand what's happening, including confirming their findings using animal studies.

Vaping illness has been an ongoing concern for both the tobacco and cannabis industries, as well as government officials and public health researchers. And with a breakthrough finally here on vaping illness, there's been a range of public responses.

For one thing, federal health officials are pushing for more comprehensive research into the safety of vaping cannabis.

And the cannabis industry is on board. As Terry Holt, a spokesperson for the National Cannabis Roundtable told The Hill, “The black market can only be addressed by a viable legal market that’s regulated and can promise safety and security for consumers."

At the same time, cannabis industry representatives in Michigan are pushing for a ban on vitamin E acetate in vape products – a ban that has already been implemented in other countries, like Canada.

The buzz around vaping illness affects the nicotine industry, too. The government is pushing to bump the age restrictions on vape products from 18 to 21, and a ban on flavored vape products is already in the works.

Identifying one of the culprits in vaping illness is a promising first step toward safer vaping – but, ultimately, vaping will never be healthier than simply not using at all. We already know that vaping has negative health effects beyond lung illness.

Take the effect on your heart. While smoking has long been linked to cardiovascular disease and stroke, vaping might cause similar health concerns. New research conducted at Boston University School reports that vaping negatively affects your cholesterol levels. Specifically, it boosts the amount of LDL cholesterol – the "bad" cholesterol linked to heart disease – and reduces the amount of HDL cholesterol, the "good" cholesterol linked to better heart health.

What's more, researchers have found that e-cigarettes might reduce blood flow more than regular cigarettes – which means that, in some ways, vaping might be worse for your health than smoking.

The bottom line? It's healthiest to simply avoid vaping products entirely. But if you plan to vape anyway, shop smart. Avoid "black market" vape products, which could have harmful additives, and stick with legal and regulated products to stay as safe as possible.