2019–2020 vaping lung illness outbreak
An outbreak of severe vaping-associated lung illness starting in 2019 is ongoing among users of cannabis vaping products, almost exclusively in the United States. The first cases were identified in Illinois and Wisconsin in April 2019; as of 21 January 2020, a total of 2,711 hospitalized cases, including 60 deaths have been confirmed by the U.S. Centers for Disease Control. Cases peaked in September 2019, and have been slowly declining since.CDC investigators identified direct exposure to chemicals present in vaping products as responsible for the outbreak.Vitamin E acetate is a very strong culprit of concern in the lung illnesses related to THC-based vaping products, but the CDC did not rule out other chemicals as possible causes. Though patients have reported using vaping products containing THC, nicotine, or both types, about 86% of patients studied by the CDC admitted THC use. The majority of those affected were young adults 18-34, which is the group with the greatest prevalence of cannabis use in the US.Nicotine-containing products are regulated in the U.S. by the Food and Drug Administration; THC products are illegal under federal law, but allowed and regulated by some states. Prior to the outbreak, vitamin E acetate was used in low concentrations, or lower than 20% of the formula in vape cartridges, as a thickening agent. As a result of a limited availability of cannabis in California as well as high demand, illicit sellers had used about 50% or higher of diluent thickeners in their formulas to bulk up tiny potency vape cartridges, and vitamin E acetate is a common choice because it resembles THC oil. Some jurisdictions took action to restrict the sale of products containing vitamin E acetate and other chemicals in response to the outbreak, but THC products in states where it is illegal and some nictotine-containing products are produced illegally (and sometimes obtained illegally in jurisdictions where legal, by underage consumers).