An outbreak of e-cigarette, or vaping, product use-associated lung injury began in 2019 among users of illegal, unregulated cannabis vaping products, almost exclusively in the United States. The first cases were identified in Illinois and Wisconsin in April 2019; as of 18 February 2020, a total of 2,807 hospitalized cases, including 68 deaths, had been confirmed. According to the U.S. Centers for Disease Control (CDC), "Vitamin E acetate is strongly linked to the outbreak...Evidence is not sufficient to rule out the contribution of other chemicals of concern, including chemicals in either THC or non-THC products".
Cases peaked in September 2019, and declined thereafter. The decline led CDC to stop reporting cases in February 2020, but as of December 2020, continued to monitor cases arriving in emergency departments. Some states continued to record new cases. As of January 2022, California had reported at least 40 cases diagnosed after February 2020. As of March 2022, cases continued to be diagnosed. At least 73 cases were diagnosed in Utah after February 2020.
CDC investigators identified direct exposure to chemicals present in illegal cannabis vaping products as the likely culprit, but did not rule out chemicals in nicotine vapes as possible causes. CDC: "No specific e-cigarette device or substance has been linked to all cases, and e-cigarettes include a variety of chemical and additives". 84% of patients studied by the CDC reported THC use. The majority of those affected were adults aged 18–34, the biggest cannabis vapers in the US.
Background Nicotine-containing products are regulated in the U.S. by the Food and Drug Administration (FDA) which has not approved any e-cigarette product for sale; THC products are illegal under federal law, but allowed by some states. The outbreak occurred against the broader rise of non-combustible tobacco and nicotine products, including e-cigarettes, heated tobacco products and nicotine pouches. These products expanded as cigarette smoking declined and tobacco companies introduced new forms of nicotine delivery. Public health authorities generally distinguish these products from combustible cigarettes: they are not risk-free, but some non-combusted nicotine products may expose adult smokers to fewer harmful chemicals if they switch completely from cigarettes. The 2019–2020 lung injury outbreak, however, was linked most to THC-containing vaping products, particularly products obtained from informal or illicit sources, and to vitamin E acetate used as an additive in some THC vape cartridges.
A 2020 review stated "Initial case reports of vaping-related lung injury date back to 2012, but the ongoing outbreak of EVALI began in the summer of 2019..." At least 19 cases of vaping-associated pulmonary injuries had been reported worldwide prior to 2019. Similar cases were reported in the UK and Japan before the outbreak.
The first case of e-cigarettes inducing lipid pneumonia was documented in the medical literature in 2012; the causative agent was identified as glycerin. Glycerin was long thought to be a safe e-liquid additive. However, formaldehyde is a known product of propylene glycol and glycerol vapor degradation, and may cause lung inflammation.
Lipid pneumonia is known to cause lung inflammation, with exogenous and endogenous factors that cause this disease.
EVALI is a diagnosis of exclusion as the symptoms are diffuse and mostly non-specific. Confirmed cases have the following features:
use of e-cigarettes in the 90 days prior to symptom onset; pulmonary infiltrates on chest CT scans; absence of pulmonary infection; no other possible alternative diagnoses.
History Prior to the outbreak, vitamin E acetate was used in concentrations under 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 used 50% or higher concentrations of diluent thickeners to add bulk to low potency cartridges. Vitamin E acetate is a common choice because it resembles THC oil.
In 2019, an outbreak of severe vaping-associated lung illness afflicted certain users of vaping products in the United States.Health, CDC's Office on Smoking and (2021-08-03). "Smoking and Tobacco Use; Electronic Cigarettes". Centers for Disease Control and Prevention. Retrieved 2024-07-23. Cases were first identified in Illinois and Wisconsin in April 2019.
In September 2019, New York Governor Andrew Cuomo instructed the state health department to issue subpoenas against three sellers of thickening agents used in illicit vaping products.
The e-cigarette industry blamed illicit vaping liquids. Juul Labs stated that some news reports state that several cases of lung illness were associated with vaping THC.
By September 2019 the CDC and FDA recommended that the public should consider not using vaping products during their investigation, particularly those containing THC or vitamin E acetate from informal sources. EVALI cases declined after September 2019.
In January 2020, the CDC continued its investigation into the outbreak of vaping-associated lung injuries. Data collected from patients showed that 82% had reported using THC-containing products. As of February 18, 2020, a total of 2,807 hospitalized cases had been reported to CDC, across all 50 states, the District of Columbia, and two US territories (Puerto Rico and US Virgin Islands). 68 deaths had been confirmed in 29 states and the District of Columbia as of February 18, 2020. Symptoms typically developed over several days but sometimes stretched to several weeks. The outbreak mainly affected young people, the largest cannabis users.
Some jurisdictions restricted the sale of products containing vitamin E acetate and other chemicals in response to the outbreak. The DEA and the FDA shut down 44 websites for advertising illegal e-cigarette cartridges.
Treatment
Treatment for EVALI varies. Around 95% of patients require hospitalization. Pharmacological management includes antibiotics and potentially antivirals as well as corticosteroids. Many hospitalized patients have also required supplemental oxygen and ventilation therapy. Most EVALI cases are resolved when the patient quits vaping.On September 6, 2019, Dr. Dana Meaney-Delman, serving as the incident manager of the Centers for Disease Control and Prevention's (CDC) 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." Of the 2,506 reported cases, information is available in the three months prior to symptom onset for 1,782 of them as of December 3, 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. Many of the samples tested by the states or by the US Food and Drug Administration (US FDA) as part of the 2019 investigation have been identified as vaping products containing tetrahydrocannabinol (or THC, a psychoactive component of the cannabis plant). Most of those samples with THC tested also contained significant amounts of vitamin E acetate. A case-control study reported vitamin E acetate in the brochoalveolar lavage fluid of 94% of 51 EVALI patients and in none in 99 healthy controls in the comparator group. The CDC reported that their findings suggest vaping products containing THC are linked to most of the cases and play a major role in the outbreak. The CDC stated that the chemical vitamin E acetate is a very strong culprit of concern in the lung illnesses related to THC-based vaping products, but did not rule out other chemicals as possible causes.
Public health recommendations The CDC recommends that the public should consider not using any vaping products during their investigation, particularly those containing THC from informal sources like friends, family, or in-person or online dealers as of 20 November 2019. The CDC recommends that e-cigarette, or vaping, products should never be used by youths, young adults, or women who are pregnant. Adults who do not currently use tobacco products should not start using e-cigarettes or vaping products, according to the CDC.
United States
Cases involved in the outbreak of severe vaping-associated pulmonary injury were first identified in Illinois and Wisconsin in April 2019. As of 18 February 2020, a total of 2,807 hospitalized cases of lung illness associated with the use of vaping products have been reported to the Centers for Disease Control and Prevention (CDC) from 50 states, the District of Columbia, and two US territories (Puerto Rico and US Virgin Islands). The potential cases of severe lung illness have been associated with the use of vaping products such as devices, liquids, refill pods, and cartridges. On 12 September 2019, the CDC no longer reported possible cases. The CDC changed its reporting methodology from counting possible cases, to reporting probable and confirmed cases where patients recently vaped, developed a breathing illness, and either had some tests that were performed to rule out infection, or testing did not show an infection. The CDC stated the possible cases are still under investigation at the state level.
As of 3 December 2019, the CDC is only reporting hospitalized vaping-associated lung illness cases and vaping-associated lung illness deaths, regardless of hospitalization status. As of 15 October 2019, the CDC has reported on 1,358 people with data on age and gender: 70% of people are male. The median age of persons is 24 years, and ages range from 13 to 75 years. 79% of persons are under 35 years old. Prevalence of lung disease attributable to vaping is likely under reported, as cases brought to the CDC are some of the most severe.
Symptoms typically develop over a period of days, but can sometimes manifest over several weeks. In many cases, patients reported a gradual start of symptoms, including: breathing difficulty, shortness of breath, and/or chest pain before being admitted to a hospital for more deliberate treatment by professional medical experts. Based on reports from several states, patients have experienced respiratory symptoms (cough, shortness of breath, or chest pain), while some have also experienced gastrointestinal symptoms (nausea, vomiting, or diarrhea) or non-specific symptoms (fatigue, fever, or weight loss).
Some cases reported mild to moderate gastrointestinal illness. Some patients have reported that their symptoms developed over a few days, while others have reported that their symptoms developed over several weeks. Some patients have reported that their gastrointestinal symptoms began before their respiratory symptoms. Fever, elevated heart rate, and elevated white blood cell count have been reported, even though no infectious disease has been identified. Many patients sought medical care in ambulatory settings, sometimes over several visits, before they were admitted to the hospital.
Many patients have required medical treatment with supplemental oxygen, including some who required assisted ventilation. Some patients have been treated with corticosteroids with demonstrated improvement. Evidence does not suggest an infectious disease is the cause of the severe pulmonary disease. Antibiotic therapy alone has not consistently been associated with clinical improvement. A handful of individuals have been re-admitted for clinical care after discharge for lung injury. The CDC does not know whether individuals who were re-admitted continued or restarted use. The range of time that the CDC is aware of for these re-admissions ranges from approximately five days after discharge, to 55 days after discharge.