Pan through this interactive timeline of North Carolina's COVID-19 outbreak and policy responses.
Ninety days after Gov. Roy Cooper announced the first case of COVID-19 in North Carolina, state and local officials are gauging the effectiveness of containment policies and when they should be lifted.
North Carolina had its highest single-day total of reported COVID-19 cases the day after the state entered Phase 2 of easing restrictions.
At his press conference on Wednesday, Gov. Cooper said the state makes decisions based on trends over a period of two weeks.
"We like to look at these statistics over a 14-day period, but when you see a couple of days of increased numbers, you have to be concerned about it," he said. "It’s one of the reasons why we are continuing to emphasize to people that we are far from being out of the woods yet with this virus, that people need to continue to take safety precautions to protect themselves, their families and other people that they may come in contact with."
Dr. Ross Boyce is an assistant professor in the Division of Infectious Diseases at the UNC School of Medicine studying the extent that healthcare workers contribute to the community transmission of coronavirus. He said the effects of a COVID-19 related policy may not be seen immediately.
"We think the incubation period for SARS-CoV-2 (COVID-19) is around four to five days, but can extend out to 14 days, which is why this is used as the amount of time people are asked to isolate after a contact," Boyce said. "In other words, if everyone in the world was put into an individual, sealed room and couldn’t spread to another person, you would expect it would be about 14 days before there are no more 'new' cases."
But with over 24,000 cases in the state, many officials are having to choose which metrics are best to determine the spread of COVID-19.
"We are looking at a number of different measures to estimate the spread of COVID-19 in Orange County, including new cases per day, percentage of tests that are positive, deaths, and Emergency Department visits related to COVID-like illnesses," said Kristin Prelipp, communications manager for the Orange County Health Department. "Each measure has its strengths and limitations, which is why looking at all of them together is the most useful for us."
Prelipp said Orange County believes the data shows its policies have limited the effects of community spread.
"One of the goals of the stay-at-home orders was to flatten the curve and reduce the number of new cases that happen all at once," she said. "We never really saw a 'spike' or surge like in other places in the country, which we think is a sign of how successful our community has been at staying home and flattening the curve."
Boyce said the best numbers to look at to determine the rate of spread largely depend on what the data is being used for.
"If you want to understand 'transmission,' you essentially need to capture all the infections, both those that have symptoms and come and get tested as well as those that don’t have any symptoms, or maybe just mild symptoms, and wouldn’t normally present for testing," he said.
Boyce said that, because many people infected with COVID-19 don't show symptoms, this is difficult to achieve.
"Because it’s hard to do that, we often use a lot of surrogate measures that we hope are reasonable estimates of the 'true' transmission rate," he said. "This includes things like the proportion of tests performed that are positive, the number of patients admitted to the hospital each day/week/month, or the number of deaths. All of these are imperfect measures, but are much easier, and cheaper, to obtain."
Dr. Mandy Cohen, secretary of the North Carolina Department of Health and Human Services, said at Wednesday's press conference that, while Saturday's spike in reported cases may be an outlier, it's a signal the pandemic is not over.
"I don’t want to take any one day to make decisions about why we look at trends, but I think that sends a signal to all of us that we really, really need to be vigilant about all of the actions that we’re taking and to take these public health safety precautions very seriously," she said.
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