After eight days of high COVID-19 hospitalization rates, North Texas dipped below the state threshold for stricter business restrictions over the weekend before jumping back up to nearly 16% on Dec. 7.

The threshold is 15%. A group of 19 counties in North Texas exceeded that number for seven consecutive days starting Dec. 3. That triggered a state executive order that closes bars and requires businesses operating at 75% capacity to scale back to half capacity.

How much longer businesses will have to stick to stricter capacities depends on the hospitalization rate for the trauma service area for North Texas.

According to the executive order, businesses may return to greater capacity once North Texas hospitalizations are below 15% for seven days in a row. The hospitalization rate for Dec. 7 was 15.87%.

A trauma service area is a geographic region served by a system of medical facilities and personnel. Counties within the same trauma service area all use the same plans to handle health emergencies. They also share resources. Patients are often transferred among facilities in the same trauma service area based on their health needs and what those facilities can accommodate, Laura Anton, press officer for the Texas Department of State Health Services, said in an email.

The trauma service area in North Central Texas is known as Trauma Service Area E. It includes Collin, Dallas, Denton and Tarrant counties along with 15 others.

Each of Texas’ 22 trauma service areas is overseen by a regional advisory council, which develops and carries out plans to handle large-scale health emergencies. The councils are made up of hospitals, doctors and nurses, colleges, and other health care providers and community groups.

By design, no two trauma service areas are the same. The statewide system was adopted in the 1990s to ensure all areas of the state had access to emergency services and trauma care, as directed by the 1989 Omnibus Rural Health Care Rescue Act.

“The governor at the time was trying to prepare Texas for disasters, things like tornadoes, hurricanes or anything that would be a mass casualty-related incident,” said Crystal Kellan, public information officer for the North Central Texas Trauma Regional Advisory Council. “But what would work normally for a small town isn’t going to work exactly the same as someplace like Dallas or Houston.”

The hospitalization rate is calculated by taking the number of confirmed COVID-19 patients occupying hospital beds and dividing it by the total number of staffed beds in hospitals in the trauma service area. This includes ICU and emergency department beds, inpatient and outpatient beds, and psychiatric beds, according to the DSHS.

Collin, Tarrant, Denton and Dallas counties saw 14%-19% of their beds filled by COVID-19 patients on Dec. 7, higher than the previous peak in July. In Cooke County to the north, the hospitalization rate was almost 77% on Dec. 3 before dropping to about 45% four days later. Nearby Fannin County, meanwhile, reported 42 active cases and no hospitalizations. All these counties are subject to the same restrictions.

Until the hospitalization rate decreases and restrictions are lifted, restaurants, retail stores, offices, manufacturing facilities, gyms, museums and libraries must operate at half capacity, per the governor's order.

Data analysis by the University of Texas Southwestern Medical Center shows the average weekly COVID-19 hospitalizations in North Texas are 65% higher in December than they were in November. The effect that the new business restrictions will have on hospitalization rates is yet to be determined, as people are generally hospitalized two weeks after being infected.