Mecklenburg’s confirmed coronavirus cases are a fraction of true total, county warns

The more than 1,200 confirmed cases of the novel coronavirus in Mecklenburg County may account for “as little as 5-10%” of actual infections, officials said Monday afternoon.

Officials warned that case counts fail to capture the “true burden” of COVID-19 as the region continues to grapple with limited testing capabilities and restricts screening to individuals with only the most severe symptoms.

Public health officials have long said the confirmed cases do not represent all cases, but this is the first time the county has quantified the gap. If the 1,200 cases comprised only 5% of the total, that would mean there are at least 24,000 cases in Mecklenburg County.

Mecklenburg officials also revealed Monday they assume 1.2% of infected patients will be hospitalized for an average stay of eight days.

“This assumption attempts to account for the underestimates in actual cases due to testing limitations,” officials said in a news release.

By comparison, 1.9% of all of all known positive cases through April 16 have led to deaths, officials said in their most recent COVID-19 demographic breakdown Friday evening. Total fatalities reached 31 in Mecklenburg County on Monday.

Mecklenburg officials say they assume 30% of hospitalized patients will require treatment in the intensive care unit for an average of 10 days. About 75% of those patients will require a ventilator for an average of eight days, officials said. There were 90 people hospitalized with the virus on April 13, the county said.

The county’s healthcare facilities are responsible for providing acute care to about 2.3 million residents in Mecklenburg and surrounding N.C. and S.C. counties, according to the news release.

Monday’s revelations come two days after The Charlotte Observer reported that county officials and hospital leaders remained tight-lipped on what parameters were used to predict the peak in cases and strain on critical healthcare resources, such as available ICU beds and ventilators. It also follows three separate inquiries to the county’s Joint Information Center on local COVID-19 modeling.

Lifting stay-at-home order?

Public Health Director Gibbie Harris said last Tuesday that Mecklenburg’s peak hospital demand would likely occur on June 8, not between mid-April and mid-May as previously anticipated.

But as Mecklenburg residents begin to successfully “flatten the curve,” officials also warned Monday that a peak date does not necessarily dictate when local stay-at-home restrictions could be relaxed.

“Having a high and low bar and tentative dates allows us to make informed decisions about when and to what degree we should act,” officials said in the release. “These models are volatile and will be updated daily. These are only one type of data informing decisions about the Stay at Home order.”

Mecklenburg’s local stay-at-home order was officially extended through April 29 to align with Gov. Roy Cooper’s executive order.

Although County Manager Dena Diorio has said it is not “realistic” to maintain current social distancing measures through June, she acknowledged officials have yet to devise a plan for gradually loosening restrictions, including re-opening businesses deemed non-essential.

COVID-19 modeling

Harris said county officials are relying on the University of Pennsylvania’s CHIME model, in addition to models from Novant Health and Atrium Health, as opposed to a widely cited University of Washington analysis.

Pennsylvania’s model, according to Harris, offers more “middle-of-the-road” projections and can be customized to reflect local conditions.

Harris said Washington’s model could be too optimistic. The university’s Institute for Health Metrics and Evaluation, for example, says North Carolina saw its peak late last week, the Observer reported Monday.

Pennsylvania’s model incorporates data on how susceptible people are to the coronavirus, as well as the total number of infected and recovered individuals.

The projected outcomes now offer a clearer picture into the potential strain on hospital resources.

For weeks, Harris has reported broader details into acute cases — often saying only that one in five cases required hospitalizations, and that adults ages 60 and older are four times more likely to be hospitalized than younger residents.

Confirmed coronavirus cases in Mecklenburg are now doubling every six days, instead of a previous rate of every 2.85 days, hospital leaders told Diorio in a letter last Wednesday.

The county is seeing roughly 40% to 50% social distancing, putting the peak at June 8 with a demand of 2,756 hospital beds on that day, Harris told Mecklenburg County leaders last week.

With only 30% social distancing, the peak would have been on May 22 with nearly 3,000 more hospital beds needed on that day.

Officials say it’s a positive development to see the peak pushed into the summer. But they emphasized a lower peak could still lead to the same number of infections — just over a longer time span.

“This allows the county and the healthcare systems to adequately prepare for extended capacity,” the county’s release said.

This story was originally published April 20, 2020 at 2:55 PM.