It started small. A man near Seattle had a persistent cough. A woman in Chicago had a fever and shortness of breath.

By mid-February, there were only 15 known coronavirus cases in the United States, all with direct links to China.

“The 15 within a couple of days is going to be down to close to zero,” President Trump said.The patients were isolated. Their contacts were monitored. Travel from China was restricted.

None of that worked. Only a small part of the picture was visible. Some 2,000 hidden infections were already spreading through major cities

We traced the hidden spread of the epidemic to explain why the United States failed to stop it.At every crucial moment, American officials were weeks or months behind the reality of the outbreak. Those delays likely cost tens of thousands of lives.