RALEIGH, N.C. (WNCN) – COVID-19 cases in North Carolina are on the rise again and the Center for Disease Control and Prevention’s Community Level map upgraded Wake County from green to yellow.

What does that mean?

The CDC said the map is to help communities decide what prevention steps to take based on the latest data.

Levels can be low (green), medium (yellow), or high (red).

They are determined by looking at hospital beds being used, hospital admissions and the total number of new COVID-19 cases. 

Wake County is one of two counties to move to yellow, or medium, on Friday.

Infectious disease expert at the UNC School of Medicine, David Wohl, has tracked COVID-19 cases in the state since the start of the pandemic.

“It’s not good when you go from green to yellow or yellow to red. It just means there are more cases out there,” Wohl said.

The latest figures show 13 percent of tests are coming back positive for COVID-19. Health officials aim for 5 percent or lower.

The availability of at-home tests mean we need to look at trends, not absolute numbers.

“Even when we didn’t have home tests, a lot of people didn’t go for a test. So, we knew, even under the best circumstances, reported cases were an underestimate,” Wohl said.

Right now, the trend is on the upswing.

The state's latest numbers show Wake County is averaging more than 500 new cases per day. It's five times higher than the rate we saw one month ago.

"You don't really need only the CDC telling you that," Wohl said. "Look at your friends. Look at your neighbors. Look at your coworkers. How many people are getting diagnosed with COVID-19?"

Wohl said the increase is due to a combination of things: more infectious subvariants, letting our guard down and lack of booster shots.

"I don't think you should wait. We're in a surge now. Now's your time to get your boosters," he said.

Even if it's been said a million times, Wohl emphasized to mask up.

"They're a tool in the toolbox to take out when we need them," he said.

And right now, Wohl said we need them.