The Swiss Cheese Covid-19 Defense

The Swiss cheese model of accident causation is a framework for thinking about how to layer security measures to minimize risk and prevent failure. The idea is that when several layers of interventions, despite their weaknesses, are properly stacked up between a hazard and a potentially bad outcome, they are able to cumulatively prevent that outcome because there’s no single point of failure. During the pandemic, health care workers and public health officials have been using the Swiss cheese model to visualize how various measures can work together to help keep people safe.

Virologist Dr. Ian Mackay has visualized the Swiss cheese Covid-19 defense in a wonderful way (pictured above). Each layer of cheese represents a personal or shared intervention — like mask wearing, limiting your time indoors w/ crowds, proper ventilation, quarantine, vaccines — and the holes are imperfections. Applied together, these imperfect measures work like a filter and can vastly improve chances of success.¹ He even added a “misinformation mouse” chewing through one of the cheese slices to represent how deceptive information can weaken these defenses.

Mackay has released this graphic under a Creative Commons license (free to share and adapt w/ attribution) and is available in English, German, French, Spanish, Korean, and several other languages. (via @EricTopol)

1. It’s interesting that the Swiss cheese model is physically how masks work to stop aerosols and droplets — like layered filters and not sieves.↩

• Covid-19
• food
• Ian Mackay
• infoviz
• science