RALEIGH, N.C. (WNCN) — New cases of COVID-19 in North Carolina have dropped by more than 35 percent during the past four weeks, a CBS17.com data analysis found.

With Gov. Roy Cooper on Friday lifting all capacity and social distancing regulations along with most mask requirements, the trends have reversed in stunning fashion just four weeks after a 30 percent increase in new cases fueled concerns about a possible fourth wave.

“People are just not getting as infected as they were before,” said Dr. David Wohl, an infectious disease specialist at the University of North Carolina’s school of medicine.

The seven-day rolling average of new cases dipped to 1,263 — the lowest it’s been since Sept. 23 — according to a breakdown of state Department of Health and Human Services data. That’s a dip of nearly 36 percent from less than a month ago, when it topped 2,000 for the last time in mid-April.

The count of patients in hospitals and the percent of tests found to be positive each day has also dropped.

Seven out of 10 counties are seeing fewer cases per capita now than they did three weeks ago, and no counties are in the red zone on newest the color-coded map DHHS releases every two weeks.

But it raises a key question: How did the state dodge that potential fourth wave of infections with vaccination rates that aren’t anywhere close to the level required for herd immunity?

Wohl says it’s because herd immunity works more like a sliding scale and less like a hard-and-fast number.

“I think for many people, when we talk about herd immunity, and we talk about 70 percent, or 75 percent, they think that there’s a line that we have to cross and then automatically the switch is switched on, and we’re protected,” Wohl said. “It’s more of a continuum. And for every incremental achievement we make with vaccinating more people, we see more protection.”

That’s best illustrated at the county level.

CBS 17 News compared the per capita case rates for each county from the past two weeks against its partial vaccination rate for adults in late March — enough time for the dose or doses of vaccine to kick in and provide protection.

“I think it’s quite a fair connection, to be honest,” said Dr. Cameron Wolfe, an infectious disease specialist at Duke University’s medical school.

Of the 14 counties with the lowest case rates so far in May, all but one had a partial vaccination rate of above 20 percent six weeks ago.

The reverse also holds up: There are 25 counties that make up the bottom quartile with the highest recent new case rates — and 21 of them had vaccination rates in the teens at that time.

“I think you can correctly say that the higher a county does with its vaccination effort, the less transmission they’re going to see,” Wolfe said.

But while the numbers have improved, it’s all relative — there’s still plenty of room for improvement. Averages that are considered good today would have been a problem last summer.

“This plateau is not a place where we want to live,” said RTI International epidemiologist Dr. Pia MacDonald.

The key, of course, is to hike those vaccination percentages even higher and combat the hesitancy and ambivalence that has emerged over the past several weeks.

“Now we have to do better,” Wohl said. “We’re not out of the woods. People are still dying. I think that’s really key. And so we have to do better. I think we have the tools. We’ve got to keep up with the vaccinations. That’s going to be key. We need more people vaccinated, and we’re getting there. I really do. I think it’s slowed down. But that doesn’t mean we’re not moving forward. We are. So that’s great.”