Editorial: Contact tracing’s slow start gives coronavirus time to get ahead

The surge in new COVID-19 case numbers in the Sunbelt and the West is so alarming that New Jersey, New York, and Connecticut now require visitors from “hot spot” states to self-quarantine. As the Philadelphia region reopens, the long-promised expansion of contact tracing — an essential tool to control person-to-person transmission — is just getting started. And as is true with testing, the amount of contact tracing underway is nowhere near what’s necessary to control the spread of the coronavirus.