OBJECTIVES: In fall 2019, several states in the US passed short-term bans on the sale of Electronic Nicotine Delivery Systems (ENDS), partially in response to an outbreak of illnesses tied to THC vaping products that received national news coverage. As ENDS products are an alternative for adult smokers to switch away from cigarettes, there may be unintended consequences for them in banning ENDS. We provide causal evidence of the impact of state-level ENDS bans on cigarette sales.

METHODS: We utilized a Generalized Synthetic Control (GSC) model to predict counterfactual cigarette sales for states that passed an ENDS ban in fall 2019, based on synthetic weights derived from states that did not pass such bans. The outcome was weekly cigarette sales per capita, based on commercial data, from Jan. 2018 - Dec. 2019. Factors that affect tobacco product sales, including smoking prevalence, tobacco taxes, inflation, unemployment, population size, and ENDS market share, are included as control variables. Fixed and random effects accounted for state and time-level variation.

RESULTS: Cigarette sales in states banning ENDS were significantly higher than would have been observed otherwise. A full ban on ENDS products increased weekly per capita cigarette sales by 12.7% in Massachusetts (p<0.001); Banning just flavored ENDS products resulted in higher than expected sales in Washington (8.3%), New York (5.7%) and Rhode Island (5.8%) (p<0.001). States that passed a ban that was later blocked (Oregon, Michigan) showed no difference in observed cigarette sales in the same period. Results were robust to a number of validation and specification checks.

CONCLUSIONS: This study provides some of the first causal evidence that banning ENDS products may have unintended consequences, such as increases in cigarette sales. Future research is needed to understand the longer-term impact of these policies.