What is already known about this topic?
E-cigarette, or vaping, product use–associated lung injury (EVALI) patients in Illinois, Utah, and Wisconsin acquired tetrahydrocannabinol (THC)-containing products primarily from informal sources.
What is added by this report?
Nationwide, most EVALI patients with data on product source reported acquiring THC-containing products from only informal sources, whereas most nicotine-containing products were acquired from commercial sources. EVALI patients aged 13–17 years were more likely to acquire both THC- and nicotine-containing products from informal sources than were adults.
What are the implications for public health practice?
While the investigation continues, CDC recommends that the best way for persons to ensure that they are not at risk is to consider refraining from the use of all e-cigarette, or vaping, products.