Pandemics seem to have a way of reminding us about things we might normally take for granted: The feel of a hug or handshake. The number of times we touch our faces or wash our hands each day. Even our intake of breath—and what it might feel like if COVID-19 blocked our ability to breathe as effortlessly as we normally do.

This is a moment in history that has many of us thinking more about our lungs than we ever have before.

Lungs do amazing things invisibly. They contain an array of around 1,200 miles of capillaries and 300 million tiny sacs. When we breathe, our heart circulates blood past those tiny gas exchangers to fuel every cell in the body.

As the SARS-CoV-2 pathogen spreads across the world, researchers are racing to figure out how this new viral foe steals that ability from us. Part of the work involves finding preexisting health factors that might allow the disease it causes to change from a bad—but beatable—respiratory bug to a deadly threat.

Early pathological studies from the pandemic have revealed some risk factors for the most severe forms of COVID-19. Among the most important: being older and having a  chronic underlying illness.

Smoking and vaping are also being actively investigated as risk factors. A wealth of research already suggests that smoking suppresses immune function in the lungs. It is also known to increase the risk  of influenza. And while there are very little data on e-cigarette use and infectious disease risk, the recent outbreak of deadly vaping-related lung illnesses sensitized both the scientific world and the public to the potential harms associated with that practice.

In this video by Scientific American’s reporting partner Retro Report, we see that while COVID-19 is brand-new, the scientific approach to treating people who get it cannot rely on understanding SARS-CoV-2 in isolation alone. Treatment must also take into account the unique history and susceptibility of each patient’s airway. Doing so means understanding, and factoring in, personal habits, including smoking and vaping.