(NEXSTAR) — A summer surge in COVID-19 cases has spiked the number of people in the hospital with serious complications from the virus. Nationwide, COVID-related hospitalizations are up 12% in the last week of available data from the Centers for Disease Control and Prevention.

But in some U.S. counties, the situation is dramatically worse. The CDC considers COVID-19 hospitalizations to be “medium” in 17 counties around the country. That means between 10 and 19.9 people are hospitalized with the virus for every 100,000 residents.

In two places in Texas, Navarro and Freestone counties, hospitalizations were up 250% in a single week – meaning they more than tripled. Fourteen new people were admitted in the past week, but because of their relatively small populations, that’s a “high” rate of people going to the hospital, according to the CDC classification.

Other areas of concern are:

• Southeast Texas (Presidio, Brewster and Jeff Davis counties): hospitalizations up 100% in one week
• Northeastern Oregon (Wallowa, Union and Baker counties)
• Central Oklahoma (Seminole, Hughes, Pontotoc and Coal counties): hospitalizations jumped 450%
• Hawaii County: hospitalizations up 64%
• Southern Nebraska (Adams, Clay, Webster and Nuckolls counties): hospitalizations up 125%
• Mohave County, Arizona: hospitalizations elevated, but dropping week over week
• Colquitt County, Georgia: hospitalizations up 67%

Nationwide, there were an additional 8,035 people admitted to the hospital with COVID-19, the CDC reports. This is the biggest spike in COVID hospitalizations since last winter, according to The Hill.

The CDC does not track infections anymore, meaning hospitalizations are one of the only data clues we have to understand how fast the virus is spreading and where.

Jill Rosenthal, director of public health policy at the Center for American Progress, told The Hill summer surges of COVID-19 may be the new norm. “We have had a summer wave of COVID for the last few summers and so it’s not surprising to see an increase in COVID right now.”

While winter means more people socialize indoors (known to accelerate the spread of the coronavirus), summer means more people are traveling and socializing overall. Plus, in hot parts of the country, people are more likely to socialize and spend time in the air-conditioned indoors than they are to be outside.

The omicron variant still appears to be dominant. According to the CDC, omicron’s many subtypes make up 99.9% of cases.