A Threshold in the Crowd: How One in Three Protected Changes the Course of an Epidemic
A crowd of pedestrians in a square moves chaotically: each person goes their own way, occasionally bumping into others. If every third person in that crowd wears a protective suit that blocks the pathogen, the rhythm of disease spread changes abruptly. That is exactly the scenario scientists reproduced by simulating 3000 self-propelled particles that repel each other and become infected upon close contact.