Revisiting a 19th Century Medical Idea Could Help Address COVID-19

Face masks. Ventilation. Air purifiers. Social distancing. Breathing has been in the news and on our minds for the past year, since the evidence became increasingly clear that the coronavirus spreads via aerosols, infectious viral particles suspended in the air. In everyday language, the coronavirus is airborne.

To protect our health, we have begun to pay attention to the air we breathe, much as people did in the 19th century, when they believed that airborne “miasmas” — vapors and gases released by decomposition — spread disease. After scientists learned more about human respiration in the late 18th and early 19th centuries, they added “vitiated air,” meaning air that had been exhaled and corrupted by someone’s body, to miasmas as likely health threats. Today’s research into how coronavirus has spread through aerosol droplets closely mirrors 19th century discussions of vitiated air.

Revisiting the history of miasma theory and its subsequent disappearance from our understandings of disease tells us that our routines for disease prevention have fluctuated with changing knowledge about disease causation. Some of these fluctuations have been beneficial, such as washing hands to reduce bacterial spread and installing window screens to diminish contact with mosquitoes.

Yet other fluctuations, such as ignoring earlier prescriptions for how to combat aerial health threats, have contributed to our current health crisis and pitched political debates over interventions. By recovering the everyday routines that Americans used to combat aerial health threats in the 19th century, we can normalize the seemingly new advice of aerosol engineers and disease experts.

In the early 19th century, medical knowledge was a fusion of ancient concepts and recent observations that explained how illnesses spread. Today we think of diseases as having specific, identifiable causes and symptoms, but in the early 19th century, people experienced illness as a set of interactions between their bodies and the world around them. Medical experts believed that a range of fevers were caused by changes in the ambient environment and that a few specific diseases, like smallpox, somehow spread from person to person.