As coronavirus has spread, Americans have become more familiar with the term “social distancing,” a reference to the cancellation of events, closure of schools, and migration to working at home, meant to minimize human contacts that can more rapidly spread the virus.

As the list of cancellations and closures has piled up, I’ve sensed a growing skepticism among some people who see this as an overreaction. So I thought it would be worth taking a moment to explain why experts say these strategies are absolutely essential if we are to avoid a catastrophe that will overwhelm our medical system and cause a massive death toll.