The American Association of Public Health Physicians recommends e-cigarettes for use as part of a harm reduction strategy.
http://www.aaphp.org/Resources/Documents/20100402AAPHPEcigLegisStatemnt.pdf
10. Harm Reduction: Smokers who have tried, but failed to quit using medical guidance and pharmaceutical products, and smokers unable or uninterested in quitting should consider switching to a less hazardous smoke-free tobacco/nicotine product for as long as they feel the need for such a product. Such products include pharmaceutical Nicotine Replacement Therapy (NRT) products used, offlabel, on a long term basis;, electronic “e” cigarettes, dissolvables (sticks, strips and orbs), snus, other forms of moist snuff, and chewing tobacco.
http://www.aaphp.org/Resources/Documents/20100402AAPHPEcigLegisStatemnt.pdf