In 1962, two years before U.S. Surgeon General Luther Terry released his famous report on the health hazards of smoking, the Royal College of Physicians (RCP) covered the same subject in a report that went further than Terry's, linking cigarettes to cardiovascular disease as well as lung cancer and chronic bronchitis. Last Thursday the RCP issued another landmark report that should inspire imitation in the United States, endorsing e-cigarettes as a harm-reducing alternative to the combustible, tobacco-containing kind.

"Large-scale substitution of e-cigarettes, or other non-tobacco nicotine products, for tobacco smoking has the potential to prevent almost all the harm from smoking in society," the RCP says. "Promoting e-cigarettes…and other non-tobacco nicotine products as widely as possible, as a substitute for smoking, is therefore likely to generate significant health gains in the UK."

The same is true for the United States, where public health officials tend to view e-cigarettes with fear rather than hope. The RCP report carefully addresses the concerns raised by critics of vaping.

Is vaping safer than smoking?

"E-cigarette vapour contains a far less extensive range of toxins, and those present are typically at much lower levels, than in tobacco smoke," the report notes. "In normal conditions of use, toxin levels in inhaled e-cigarette vapour are probably well below prescribed threshold limit values for occupational exposure, in which case significant long-term harm is unlikely. Some harm from sustained exposure to low levels of toxins over many years may yet emerge, but the magnitude of these risks relative to those of sustained tobacco smoking is likely to be small….Although it is not possible to quantify the long-term health risks associated with e-cigarettes precisely, the available data suggest that they are unlikely to exceed 5% of those associated with smoked tobacco products, and may well be substantially lower than this figure."

Similarly, a 2015 report from Public Health England said "it has been previously estimated that [electronic cigarettes] are around 95% safer than smoking," which "appears to remain a reasonable estimate." Given this huge difference in risk, it is completely irresponsible for government officials and medical authorities to discourage smokers from switching to vaping by implying (or stating outright) that tobacco-free, noncombustible e-cigarettes are just as dangerous as the real thing.

The RCP argues that appropriate safety regulations could further reduce the hazards posed by e-cigarettes. But it warns that if regulation "makes e-cigarettes less easily accessible, less palatable or acceptable, more expensive, less consumer friendly or pharmacologically less effective, or inhibits innovation and development of new and improved products, then it causes harm by perpetuating smoking."

Do e-cigarettes help smokers quit?

"Smokers who use nicotine products as a means of cutting down on smoking are more likely to make quit attempts," the RCP says. "Promoting wider use of consumer nicotine products, such as e-cigarettes, could therefore substantially increase the number of smokers who quit."

In England, the RCP notes, e-cigarettes have surpassed nicotine replacement therapy (NRT, i.e., gum, patches, nasal spray, etc.) as an alternative to smoking. While the evidence so far is limited, it suggests that e-cigarettes are at least as effective as NRT in helping smokers quit, and there is reason to believe they will work better for many people, since vaping more closely resembles the activity it is supposed to replace.

The National Health Service's Stop Smoking Services (SSSs) recently started to help smokers trying to quit with e-cigarettes, and the early data are promising. "The average quit rate in all smokers using SSSs was around 51%, and among e-cigarette users it was 66%," the RCP reports. "Although factors other than the product itself are likely to be involved in this difference, the finding is certainly consistent with high efficacy as a cessation therapy."

Data from England indicate that "smokers who use e-cigarettes at least daily are indeed twice as likely to make a quit attempt, or else to reduce their smoking, [as] those who do not." Although that study did not find that e-cigarette use made success more likely, "independent clinical trials and observational data from the Smoking Toolkit Study [a British survey] indicate that e-cigarette use is associated with an increased chance of quitting successfully."

Are e-cigarettes a gateway to smoking?

Critics of e-cigarettes worry that they will "renormalize" smoking and increase its incidence by fostering nicotine addiction among people who otherwise never would have used tobacco. But there is very little evidence that is happening. To the contrary, smoking rates and vaping rates are moving in opposite directions, and regular use of e-cigarettes does not seem to have much appeal among people who have never smoked.

"There is no evidence that either NRT or e-cigarette use has resulted in renormalisation of smoking," the RCP says. "None of these products has to date attracted significant use among adult never-smokers, or demonstrated evidence of significant gateway progression into smoking among young people."

If there were a significant gateway effect, surveys should identify people who have never used tobacco but who regularly use e-cigarettes (often enough to get hooked on nicotine) and eventually move on to smoking. But if such people exist, there are not many of them.

"E-cigarette use in Britain is, to date, almost entirely restricted to current, past or experimental smokers," the RCP notes. "As with NRT, there is no evidence thus far that e-cigarette use has resulted, to any appreciable extent, in the initiation of smoking in either adults or children; the extremely low prevalence of use of e-cigarettes among never-smoking adults and children indicates that, even if such gateway progression does occur, it is likely to be inconsequential in population terms."

By contrast, the impact of turning large numbers of smokers into vapers could be dramatic. "The growing use of electronic cigarettes as a substitute for tobacco smoking has been a topic of great controversy, with much speculation over their potential risks and benefits," says John Britton, chairman of the RCP's Tobacco Advisory Group. "This report lays to rest almost all of the concerns over these products, and concludes that, with sensible regulation, electronic cigarettes have the potential to make a major contribution towards preventing the premature death, disease and social inequalities in health that smoking currently causes in the UK. Smokers should be reassured that these products can help them quit all tobacco use forever."

This article originally appeared at Forbes.com.