COVID-19 test positivity has ticked up nationally, reaching its highest level since February, according to CDC surveillance data tracking respiratory virus activity.
A June 2026 CDC outlook had anticipated more summer transmission in Southern and Western states that saw comparatively little COVID-19 activity over the 2025-2026 winter, reasoning those regions would have lower recent immunity from infection heading into the summer — a pattern now playing out in the latest data.
Here are six things to know:
- COVID-19 test positivity reached 4.8% as of Aug. 15, the highest rate since 4.5% on Feb. 14.
- COVID-19 cases are climbing in at least 40 states as summer winds down.
- CDC’s wastewater surveillance data classifies national COVID-19 activity as “very low,” while WastewaterSCAN, a Stanford University-run infectious disease monitoring program using different methodology, rates activity as “high” nationwide.
- The West and South are showing the highest wastewater concentrations and the sharpest case increases so far this season.
- CDC’s ARI (acute respiratory illness) tracker, which measures emergency department visits tied to COVID-19, flu and RSV, remains a key early indicator alongside test positivity and wastewater data for spotting rising transmission.
- Flu and RSV activity remain low nationally, meaning the traditional fall respiratory illness season has not yet begun even as COVID-19 cases rise.
