A lot of people tend to think that smoke from cigarettes and vapor from E cigarettes are more or less the same thing. However, aside from looking similar when being exhaled, both of these things are quite different and affect you differently. Smoke produced by burning cigarettes is something that comes around because of combustion. With combustion a number of chemicals are produced and released that are inhaled by us. Aside from just the treated paper and tobacco in the cigarette, a number of new compounds are made through the oxidation process. So the inhaled smoke actually has a number of new chemicals that were not there initially. Another thing to note about smoke is that smoke can actually not be present without fire burning something.
Vapor on the other hand is very different from smoke. Vapor is created because a substance is able to reach a temperature where it is turned into the gaseous state. This temperature is lower than the point of combustion and is simply the same chemicals and materials changing to a gas state and does not lead to any new chemicals forming in some way. So with vapor no new compounds are formed and no new chemicals enter you rather than the ones already present.
The key to not having your health be affected as badly by vaping is to make sure that the supplier of vaping products you have is not using any material in their vapes that are not approved by the FDA or other relevant bodies. With all the chemicals being approved, there will be no real issue with the vapor from the vapes affecting you too badly in ways that you do not fully understand. It can be a much safer alternative to smoking cigarettes, even if not fully safe.