[0]: "
Studies suggest nicotine vaping may be less harmful than traditional cigarettes when people who regularly smoke switch to them as a complete replacement."
[1]: "Vaping Is Less Harmful Than Smoking, but It’s Still Not Safe"
[1] has some problems. It seems to be conflating the vitamin E acetate issue with vaping in general. ("However, there has also been an outbreak of lung injuries and deaths associated with vaping. As of Jan. 21, 2020, the Centers for Disease Control and Prevention (CDC) confirmed 60 deaths in patients with e-cigarette, or vaping, product use associated lung injury (EVALI).") The section on "Research Suggests Vaping Is Bad for Your Heart and Lungs" focuses on nicotine. Which raises your blood pressure. And not much else, according to other sources.