COVID-19 infections are rising across much of the United States as summer comes to an end, according to the latest data from the Centers for Disease Control and Prevention (CDC).

While the agency continues to classify overall COVID-19 activity nationwide as "very low," recent surveillance shows cases increasing in 48 states, continuing the seasonal pattern often referred to as the "summer surge."

Health experts say COVID-19 has consistently shown a tendency to increase not only during the traditional winter respiratory virus season but also in late summer. They attribute the trend to a combination of factors, including increased indoor gatherings in air-conditioned spaces, the return to school, changing immunity levels, and the virus's natural transmission patterns.

"COVID-19 is increasing nationally, but from a relatively low baseline," infectious disease epidemiologist Dr. Syra Madad previously told USA TODAY. She noted that the rise first became noticeable in parts of the South and West before expanding across the country in late July and early August.

Cases rising in nearly every state

CDC estimates through Aug. 26 indicate that COVID-19 infections were either growing or likely growing in 48 states. Iowa did not report sufficient data, while Rhode Island and Washington, D.C., showed little change compared with the previous week.

Texas reports the highest viral activity

Wastewater surveillance, which helps public health officials monitor virus circulation before many cases are confirmed through testing, shows the highest levels of COVID-19 activity remain concentrated in the South.

For the week ending Aug. 22:

• Texas recorded very high COVID-19 activity.

• Mississippi reported high activity.

• California, Nevada, Florida, Rhode Island, Louisiana, and Washington were classified as having moderateactivity.

• Most remaining states continued to report low or very low levels of viral activity.

Although infections are increasing across much of the country, health officials emphasize that national COVID-19 activity remains relatively low overall. They continue to encourage people—particularly older adults and those at higher risk of severe illness—to stay informed about local conditions and take appropriate precautions when needed.