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. He even added a “misinformation mouse” chewing through one of the cheese slices to represent how deceptive information can weaken these defenses.