page_title: 2019–2020 vaping lung illness outbreak
section_title: Investigation
hierarchical_section_title: 2019–2020 vaping lung illness outbreak / Investigation
caption_attribution_description: Acting FDA Commissioner Ned Sharpless, M.D. takes a tour of the FDA’s Forensic Chemistry Center. The Center serves as the FDA’s premier national laboratory and is playing a critical role in fact-gathering and analysis for the ongoing incidents of lung illnesses following vaping product use.
context_page_description: 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.
context_section_description: Investigators from multiple states in the US are collaborating with the Centers for Disease Control and Prevention (CDC) and the US Food and Drug Administration (US FDA) to determine the cause of the lung illnesses associated with the use of vaping products.
  On 6 September 2019, Dr. Dana Meaney-Delman, serving as the incident manager of CDC's response to this outbreak, said that "Based on the clinical and laboratory evidence to date, we believe that a chemical exposure is likely associated with these illnesses. However, and I really want to stress this, more information is needed to determine which specific products or substances are involved. We are aware that some laboratories have identified vitamin E acetate in product samples, and we have connected those laboratories with the FDA Forensic laboratories to compare results. At this time, no one device, product, or substance has been linked to all cases. Continued investigation is needed to better understand if a true relationship exists between any specific product or substance and the illnesses observed in patients. To find the answer we will need to combine information about e-cigarette use, and product sample testing and the clinical information from patients."
  Patients have acknowledged recent use of tetrahydrocannabinol (THC)-containing e-cigarette products while speaking to healthcare personnel, or in follow-up interviews by health department staff. On 6 September 2019, The New England Journal of Medicine reported that "Information on product use is based on reports by the patients, and patients may be reluctant to report illicit drug use." On 2 October 2019, The New England Journal of Medicine reported that the histologic evidence suggests that the "vaping-associated lung injury represents a form of airway-centered chemical pneumonitis from one or more inhaled toxic substances rather than exogenous lipoid pneumonia as such, but the agents responsible remain unknown." They also stated that this "finding should be interpreted with caution." On 17 October 2019, the American Journal of Clinical Pathology reported that lung biopsies from eight patients with vaping-associated lung injury show acute lung injury patterns, not exogenous lipoid pneumonia.
  Of the 2,506 reported cases, information is available in the three months prior to symptom onset for 1,782 of them as of 3 December 2019. 80% reported THC use, 35% reported exclusive THC use, about 54% reported using nicotine-containing products, and 13% reported exclusive use of nicotine-containing products. The CDC reported that their findings suggest vaping products containing THC, particularly those obtained off the street or from other informal sources (e.g. friends, family members, illicit dealers), are linked to most of the cases and play a major role in the outbreak.
  On 8 November 2019, Dr. Anne Schuchat, principal deputy director of the CDC, said, "for the first time we have detected a potential toxin of concern — Vitamin E acetate — in biologic samples from patients with lung injuries associated with the use of e-cigarette or vaping products." The sample types were bronchoalveolar lavage (BAL) fluid samples (fluid samples collected from the lungs). The chemical was found in samples collected from ten different states from the lungs of 29 patients with the disease. "These findings provide direct evidence of Vitamin E acetate at the primary site of injury within the lungs," said Dr. Schuchat. The CDC tested for a wide range of substances that might be found in e-cigarette or vaping products including plant oil, petroleum distillates like mineral oil, medium-chain triglyceride oils – or MCT oils – and terpenes which are compounds found in or added to THC products. No other potential toxicants were detected in the testing conducted so far. The CDC did not rule out other possible compounds or ingredients that may be causing the lung injuries. No one compound or ingredient has emerged as the cause of these illnesses so far; and it may be that there is more than one cause of this outbreak.
  Many of the samples tested b
caption: US FDA's Forensic Chemistry Center.[38]
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