Our findings suggest that e-cigarettes are not neutral in terms of the effects on the lungs," said senior author Shyam Biswal, a professor in the Department of Environmental Health Sciences at the Bloomberg School. "We have observed that they increase the susceptibility to respiratory infections in the mouse models. This warrants further study in susceptible individuals, such as COPD patients who have switched from cigarettes to e-cigarettes, or to new users of e-cigarettes who may have never used cigarettes