RALEIGH, N.C. (WNCN) — COVID-19 testing levels across North Carolina continue to fall, down more than 30 percent from their mid-January peak, and the hard-to-explain drop that coincides with the rise in the availability of the vaccine in the state, a CBS17.com data analysis found.

“I’m not sure why testing numbers are down,” said Dr. David Wohl, an infectious disease specialist at the University of North Carolina’s school of medicine.

The decline is particularly worrisome for several reasons, Wohl said. Even as the state’s key COVID-19 metrics have shown significant improvement over the past six weeks, consistently high levels of testing is a key mitigation strategy.

COVID-related hospitalizations Friday were less than a third of what they were at the peak in January. The seven-day rolling average of new cases is at its lowest level since October. And the past two days saw two of the state’s three lowest daily percent positive rates on record.

“Either we are seeing fewer people get sick and then maybe exposing others who want to get tested, or people are reluctant to get tested,” Wohl said. “I think it’s the former, not the latter.”

Testing peaked across North Carolina in mid-January, when the seven-day rolling average of daily tests rose to 67,030 on Jan. 16. That figure dropped to 45,225 on Sunday. More recent testing numbers tend to be unreliable and subject to change as backdated tests are processed and recorded.

That continues a trend uncovered by a previous CBS17.com data analysis: From mid-January to early February, the decline was 20 percent.

January was also when the state’s weekly average of vaccine doses administered rose dramatically, surpassing 300,000 shots for the first time during the week of Jan. 18 and remaining at approximately that level during the five weeks that followed.

The loosening of some COVID-19 restrictions in other states could have a domino effect in North Carolina that robust testing could help the state avoid. Texas and Mississippi lifted their mask mandates and rolled back restrictions.

“Certainly, seeing that other states have opened up widely. … Those people travel to places like North Carolina,” Wohl said. “So I really am very concerned, to be honest, that we might see an uptick in cases because of the rapid opening in other parts of the country.”

Testing is critical in keeping track of the new coronavirus mutations that could allow it to spread more easily, cause more severe symptoms or become more resistant to the more omnipresent vaccines. 

Durham County last week reported its first confirmed case of a more contagious strain of the virus.

“Testing is really important because testing can help us understand more about these new variants, because some proportion of the viruses that are detected in people can be sequenced — we can look at the genes and see if it’s one of these variants,” Wohl said. “We want to know more about how many people have COVID and whether or not they have variants.”

CBS 17’s Joedy McCreary has been tracking COVID-19 figures since March 2020, compiling data from federal, state, and local sources to deliver a clear snapshot of what the coronavirus situation looks like now and what it could look like in the future.