Fig. 3

The “Swiss cheese model” of accident causation (more accurately called Emmental or Emmentaler cheese model [104]) originated with James T. Reason and Rob Lee in the 1990s (and was potentially influenced by other researchers) [105, 106, 107]. As applied to COVID-19 [34, 108, 109, 110, 111], this model recognizes the additive success of using multiple preventive interventions to reduce the risk of SARS-CoV-2 infection. No single slice of cheese (public health strategy) is perfect or sufficient at preventing the spread of SARS-CoV-2. Each slice has holes (inherent weaknesses or limitations) with variable number, size, and location over circumstances or time, which may allow viral transmission. SARS-CoV-2 infection occurs when multiple holes happen to align at the same time permitting a trajectory of successful transmission. When several interventions are used together and consistently and properly, the weaknesses in any one of them should be offset by the strengths of another. The preventive interventions can be broken into personal and shared, although some interventions may be both. The order of the slices and holes in the illustration are not reflective of the degree of effectiveness of the interventions, given that the scenarios of transmission are variable and complex. The black rats eating the slices of cheese represent factors undermining prevention efforts while the extra cheese represents a source of factors and opportunities favoring prevention efforts. This infographic was designed for this manuscript and was inspired by previous illustrations by the Cleveland Clinic [108], Sketchplanations [109], and virologist Ian M. Mackay, who proposed the Swiss Cheese Respiratory Pandemic Defense [34, 110]