Birx told hundreds of emergency managers and other state and local leaders that they should act quickly to stem the outbreaks. Among her recommendations were to trace the contacts of patients testing positive for COVID-19 in areas where test positivity is going up.

“When you first see that increase in test positivity, that is when to start the mitigation efforts,” she said in a recording obtained by Public Integrity. “I know it may look small and you may say, ‘That only went from 5 to 5-and-a-half [percent], and we’re gonna wait and see what happens.’ If you wait another three or four or even five days, you’ll start to see a dramatic increase in cases.”

Birx said the federal government was seeing encouraging declines in test positivity in places like Phoenix and San Antonio but warned that the outbreak in the Sunbelt was moving north.

“What started out very much as a southern and western epidemic is starting to move up the East Coast into Tennessee, Arkansas, up into Missouri, up across Colorado, and obviously we’re talking about increases now in Baltimore,” she said. “So this is really critical that everybody is following this and making sure they’re being aggressive about mitigation efforts.”