A lung injury outbreak that peaked in one week and then fell

**As of 14 January 2020, all 50 states, the District of Columbia, the US
Virgin Islands and Puerto Rico had reported 2,668 hospitalised EVALI
patients** — e-cigarette, or vaping, product use-associated lung injury.

The shape of the curve

Cases peaked during the week of 15 September 2019, and the weekly number of
hospitalised patients has since steadily declined. Emergency department
visits related to e-cigarette or vaping products, tracked through the
National Syndromic Surveillance Program, show the same shape: **sharply
increasing in August 2019, peaking in September, declining since.**

An outbreak that rises and falls that fast usually means a specific
contaminated supply rather than a general property of the product — which is
what the investigation found.

What is strongly linked, and what is not ruled out

**Vitamin E acetate is strongly linked to the EVALI outbreak and should not
be added to any e-cigarette, or vaping, products.**

It is an additive in THC-containing products, and it fits the 82%.

The report is then careful in a way worth preserving rather than rounding off:

**However, evidence is not sufficient to rule out the contribution of other
chemicals of concern, including chemicals in either THC- or non-THC–
containing products, in some reported EVALI cases.**

14% of patients reported exclusively nicotine-containing products. That
group cannot be explained by an additive found in THC products, and the
recommendation does not pretend otherwise.

The recommendation

**Do not use THC-containing e-cigarette or vaping products, especially those
acquired from informal sources** — friends, family members, or in-person or
online dealers. The informal supply is the one nobody inspects, which is where
an additive nobody intended ends up in a cartridge.

**Clinicians and public health practitioners should remain vigilant for new
EVALI cases.** A declining curve is not a closed one, and a 24-year-old with
unexplained lung injury is still a question to ask about vaping.

Source: Centers for Disease Control and Prevention, MMWR.