Public health officials who see the rise of vaping as a sinister development, rather than an opportunity to dramatically reduce smoking-related disease and death, insist on calling e-cigarettes "tobacco products," even though they do not contain tobacco. The bizarre consequences of that scientifically unsound label can be seen in a recent press release from the U.S. Centers for Disease Control and Prevention (CDC) that deliberately obscures a decline in teenagers' tobacco use by pretending it did not happen.

Each year the CDC's National Youth Tobacco Survey asks high school and middle school students about their use of six tobacco products: cigarettes, bidis (leaf-wrapped cigarettes), cigars, pipe tobacco, shisha (used in hookahs), and smokeless tobacco. According to data published on Friday, teenagers' consumption of all but one tobacco product fell between 2011 and 2015. The only exception was hookahs, use of which rose from 2011 to 2014 before falling last year in both age groups. But hookahs are not nearly as popular as cigarettes were in 2011: The rate of past-month hookah use by high school students last year was about 7 percent, compared to 16 percent for cigarettes in 2011. So the CDC is contradicting its own data when it announces that there was "no decline in overall youth tobacco use since 2011."

The CDC reaches that puzzling conclusion by treating tobacco-free, noncombustible e-cigarettes as equivalent to the conventional kind. Instead of welcoming the substantial decline in past-month cigarette smoking among teenagers, which fell from 15.8 percent in 2011 to 9.3 percent in 2015, it bemoans the dramatic increase in past-month vaping, which rose from 1.5 percent in 2011 to 16.5 percent in 2015. As far as the CDC is concerned, the rise of vaping completely erases the progress represented by the decline in smoking.

Given the enormous difference between the risks posed by smoking and the risks posed by vaping (which is something like 95 percent less hazardous), that position is scientifically absurd. When vaping replaces smoking, that should count as a public health victory, not a setback. To the extent that teenagers who otherwise would be cigarette smokers are using e-cigarettes instead (a development that is consistent with the fact that smoking and vaping rates are moving in opposite directions), the CDC should be celebrating.

The CDC worries that teenagers who otherwise never would have tried tobacco will start vaping, get hooked on nicotine, and then move on to smoking. There is very little evidence that e-cigarettes are a "gateway" to the real thing, a fear that seems inconsistent with the ongoing declines in smoking among both adults and teenagers. While past-month use of e-cigarettes has shot up among teenagers in recent years, it may consist mainly of experimentation. Data from other surveys indicate that almost all regular vapers are current or former smokers.

The CDC also overlooks the fact that the vast majority of teenagers who try vaping use nicotine-free e-liquids. In the 2014 Monitoring the Future Study, only 22 percent of high school seniors who vaped "reported inhaling nicotine." So when the CDC equates adolescent vaping with tobacco use, it is mainly talking about products that not only do not contain tobacco but do not even contain the same psychoactive ingredient as tobacco.

Even if there were a stronger basis for the CDC's concerns, they would not justify lying to the public about adolescent tobacco use, which contrary to what the agency says is falling, not flat. "Overall tobacco use by middle and high school students has not changed since 2011," says the CDC. That simply is not true, and no amount of rhetorical wriggling can make it so.