A single negative result on an at-home COVID-19 test does not rule out infection, and the Food and Drug Administration says most people should test again rather than treat that first result as final.
The guidance matters more right now than it has in months. COVID-19 activity has been climbing across most of the country through late summer. The Centers for Disease Control and Prevention's epidemic trend model estimated that as of Aug. 26 infections were growing or likely growing in 48 states, declining in none, and holding steady in two. Test positivity tracked in the agency's respiratory virus activity data crossed 3 percent for the week ending Aug. 8, the first time since March, and continued rising into late August, with the South and West reporting the highest rates. The most recent weeks of that data are preliminary and are commonly revised. Wastewater networks have disagreed on how to characterize the level, with CDC rating national activity very low against its historical baseline while independent programs describe the same signal as elevated.
