Hannah Mckay / Reuters A man vapes outside Southwark Crown Court in London, Britain, September 25, 2017.

The National Health and Medical Research Council (NHMRC) is being urged to conduct a thorough review of the latest science surrounding e-cigarettes, with evidence suggesting they could save half a million Australian smokers from tobacco related deaths. A group of 70 Australian health researchers and clinicians signed a letter urging the NHMRC to commission an open the review, arguing the latest evidence suggests that e-cigarettes are significantly less harmful than smoking and could lead to substantial improvement in public health.

It's hoped a new review would take a harm reduction perspective. The push comes as a parliamentary inquiry into the use and marketing of e-cigarettes and personal vaporisers in Australia conducts a public hearing in Melbourne. E-cigarettes: A Primer The modern e-cigarette is often credited to Chinese pharmacist Hon Lik, who invented the product in 2003.

The value of global sales of e-cigarettes was estimated to be 3.5 billion US$ in 2015

Studies suggest the majority of adults using e-cigarettes are current cigarette users, and some suggest vaping is often motivated by a desire to quit cigarettes.

A number of global tobacco control researchers have said e-cigarettes are less harmful than tobacco Source: Tobacco Control, November 2016. "E-cigarettes are being used by smokers and ex-smokers as a less harmful alternative to an existing consumer product -- combustible tobacco -- that prematurely kills up to two thirds of its long-term users," said Associate Professor Colin Mendelsohn from the University of New South Wales School of Public Health and Community Medicine. "The science on e-cigarettes has evolved substantially since the NHMRC did its previous review, so it is time to look at what the latest research tells us about their potential for reducing tobacco-related death and disease in Australia." E-cigarettes heat a liquid nicotine juice into an vapor, which users then inhale. The vapor devices can also be fitted with nicotine-free liquids, which is legal. Currently, using the nicotine-based products in Australia is illegal because it is classed as a poison by the Therapeutic Goods Administration. But Australians are still importing the drug to mix in with their juice to use e-cigarettes as a tool to quit smoking. The Australian Drug Law Reform Foundation said increasing the quit rate is particularly important now. "Australia's smoking rate has not declined significantly over the last three years for the first time in decades, according to the (2013-2016) National Drug Strategy Household Surveys," said ADLRF President Dr Alex Wodak. "E-cigarettes appear to be contributing to the faster decline in smoking rates in other countries where they are freely available."

Getty Images/iStockphoto A young smoker inhales on an e-cigarette, or 'vape.'

Others have gone further. On Wednesday, Menzies School of Health researcher Dr Marita Hefler called for a total ban on cigarettes, arguing the evolution of alternative nicotine products, including e-cigarettes, meant it was now possible to ban combustible tobacco. Tobacco giant Philip Morris is expected to tell a parliamentary inquiry on Thursday advances in technology have transformed its business away from cigarettes in favour of smoke-free alternatives as it pushes to legalise reduced-risk alternatives to its products. (The Australian Medical Association has in the past slammed research from British American Tobacco claiming eight in 10 medical health practitioners support the use of e-cigarettes). Earlier this week a study by Georgetown University Medical Centre and published in Tobacco Control calculated the widespread uptake of e-cigarettes by smokers in the U.S. could prevent 6.6 million premature smoking-related deaths over 10 years, after allowing for any risks from vaping. "Even the gloomiest analysis shows a significant gain in years of life if nicotine is obtained from vaping instead of much more deadly amount of toxicants inhaled with cigarette smoke," said David Levy, professor of oncology at Georgetown Lombardi and the report's lead author.

HOT TOPIC | Tobacco giant Philip Morris is pushing for e-cigarettes to be legalised in Australia.#sun7 | @TomElliott3AW | @JaneCaropic.twitter.com/XHpqVS0GFY — Sunrise (@sunriseon7) October 4, 2017

"In Australia, this represents preventing about half a million premature smoking-related deaths in long-term smokers," Mendelsohn said. "These calculations support the role of e-cigarettes in Australia as a valuable strategy to kick start the decline in smoking again. The potential benefits to public health are huge." But the University of California's Dr. Stanton Glantz told ConsumerAffairs he was unimpressed with Levy's study. "If you can snap your finger and get all the smokers to switch to e-cigarettes with no other effects, there's no question we would be better off. But that's not what is happening," Glantz said. "I don't think this paper contributes much of anything frankly," he added.