On Feb. 13, Health and Human Services Secretary Alex Azar told a Senate committee that five cities — Chicago, Los Angeles, New York, San Francisco and Seattle — were working with the CDC on an early warning network of expanded testing. Honolulu was added later.

On Feb. 13, Health and Human Services Secretary Alex Azar told a Senate committee that five cities — Chicago, Los Angeles, New York, San Francisco and Seattle — were working with the CDC on an early warning network of expanded testing. Honolulu was added later.