Impact of e-cigarettes on oral microbiota and risk of infection

Does vaping promotes mouth infections by causing an imbalance in the oral microbiota? A study has attempted to prove this theory while casting doubt on the safety of electronic cigarettes.


E-cigarettes are extremely popular among young Americans since they are used by more than 20% of high- school students and almost 5% of junior high students in the United States. Portrayed until now as a healthy alternative to tobacco, they no longer seem so harmless. The latest generation of e cigarettes have nicotine and toxicity levels comparable to those of tobacco and are thought to be responsible for a cascade of inflammatory reactions through their effect on the oral microbiota. However, a study published in 2018 had cleared e-cigarettes of having any adverse effects on the gut, mouth or saliva microbiotas.

Oral microbiota imbalance among vapers

To measure the impact of vaping on the oral microbiota, a team divided around a hundred volunteers into three groups: smokers (half a pack per day on average), vapers (half an e-cigarette per day) and non-smokers. Their first finding was that the severity index of tooth, gum and mouth diseases among vapers (42.5%) was significantly lower than among smokers (72.5%), but markedly higher than among non-smokers (28.2%). The second finding was that vapers showed an imbalance (dysbiosis) of the oral microbiota comparable to that of smokers. Their saliva was generally richer in bacteria than that of non-smokers, and displayed proliferation of various species harmful to oral health. In addition, human cells exposed to e-cigarette aerosols show increased sensitivity to bacterial infections compared to cells exposed to air.

Understanding long-term effects

According to the authors, the results of this study–carried out both on human subjects (in vivo) and on cells (in vitro)–confirm that vaping leads to an imbalance of the oral microbiota and increases susceptibility to infections (cavities, periodontitis*). However, this link remains to be proven, and more in-depth studies on the overall effects of vaping on oral, respiratory and cardiovascular health, particularly over the long term, seem necessary.


*inflammation of the membrane surrounding the teeth



Pushalkar S., Paul B., Li Q., et al. Electronic Cigarette Aerosol Modulates the Oral Microbiome and Increases Risk of Infection. iScience. 2020; 100884.;