RALEIGH, N.C. (WNCN) — The decision to move North Carolina into the second phase of the reopening process might have come before state leaders could gauge the full effect of its shift into Phase One.
According to the Centers for Disease Control and Prevention, the incubation period of the coronavirus can last as long as 14 days.
That’s two days longer than the time that elapsed between the start of reopening and Gov. Roy Cooper’s announcement of the decision to move to the next stage of the process.
That means it’s possible that someone who might have become infected early in the first phase is not yet symptomatic as the second phase begins.
The state is monitoring four key data trends — the number of COVID-19 cases, the percent of tests that come back positive, the occupancy rates of hospitals and the number of people who visit emergency departments with flu-like symptoms — as it evaluates its step-by-step reopening process.
But each of those trends carries a specific lag — it takes time for an infected person to show symptoms, and even more time for that person to obtain a test or visit the hospital.
Pia MacDonald, an epidemiologist and expert at RTI International, told CBS 17 News that she would prefer “a minimum of 14 days” of data be collected before making any decisions.
“There are so many different factors to look at and we just need to be tracking all of this with time to get a better understanding of where we are with the outbreak,” MacDonald said.
One trend that MacDonald called “worrisome” is the growing number of cases.
The decision came only four days after the state set a single-day high with 853 confirmed cases, and the seven-day rolling average peaked Tuesday at 622 before slipping to 615 Wednesday.
That could be a function of increased testing — and the percent of tests that come back positive is a helpful metric in evaluating that. That seven-day rolling average has stabilized recently near 6 percent.
“That has just now in the last week gotten pretty stable, but we’d want to see it stable for a lot longer period of time than just a week,” MacDonald said.
According to the CDC, the average incubation time is 4-5 days, and it cited one study that determined that 97.5 percent of people with COVID-19 who develop symptoms will do so within 11 1/2 days of infection.
DHHS Secretary Mandy Cohen called the hospitalization numbers “a lagging indicator” because of the delay involved.
According to Chuck Dinerstein of the American Council on Science and Health, hospitalization follows infection in an average of 5-10 days.
Those figures have climbed recently, with a single-day high of 585 people in the hospital Tuesday contributing to a 14-day rolling average of 506 that is two shy of its high.
Cohen says the state’s hospital capacity mitigates those relatively high numbers.
“We’re trying to look at that in the context of, is our health system able to handle the number of cases? And the answer is overwhelmingly yes,” she said. “The overall message is stability there, and our system is able to have the capacity to handle additional infections should they come our way.”