One-day surge in reported COVID-19 cases attributed to data backlog

A woman is tested for COVID-19 in a parking lot in Richmond where the health department set up a temporary walk-up testing center. (Ned Oliver/Virginia Mercury)

A surge of new COVID-19 cases on Virginia’s daily dashboard was attributed to a data backlog earlier this week.

The Virginia Department of Health registered 2,015 new cases on Friday — a significant increase from the state’s typical numbers, which have largely hovered between 900 and 1,300 daily reported infections since the beginning of August. VDH spokeswoman Maria Reppas said the error originated with the department’s “system-managed flow” of data, which queues pending cases before reporting them publicly.

“The process to clear this queue ran three times a day,” she wrote in an email on Friday. “However, since the volume of data has increased, the existing frequency of running this process needed to change to avoid any backlogs in processing. While this process has been running hourly, that frequency still was not sufficient to clear the queue.”

The system is now running every 30 minutes to prevent another backlog, Reppas added.

The rapid rise came after Virginia appeared to make progress by holding its daily number of new cases steady throughout the first week of August. The commonwealth — like most of the country — has been working to curb an increase in new infections throughout July, with a seven-day average that peaked at 1,100 daily new cases on July 27.

Just yesterday, that seven-day average appeared to have declined to 995. But Friday’s addition pushed it back to 1,142 — close to the state’s previous peak of 1,195 average new daily cases on May 31, according to data from the Virginia Department of Health.

Dr. William Petri, an infectious diseases specialist at the University of Virginia, said it’s possible that the state’s average will restabilize after the sudden increase and continue to show a steady pattern of new cases. Earlier this month, Virginia was recording a seven-day average of just over 1,000 cases — a promising sign after a month of rising infections.

“My take on it is that it’s great that the numbers aren’t going up, but it’s bad that they’re not going down,” Petri said. He pointed out that Virginia’s numbers have consistently remained middle-of-the-pack throughout the COVID-19 pandemic, without the dramatic surges seen in some states, such as Florida or Texas, but also without the significant improvements made by some hard-hit states.

Friday wasn’t the first time that there have been lags or issues with the state’s daily reporting, which has undergone several significant changes since the start of the pandemic. In June, there was a sharp one-day increase in the recorded number of PCR tests after VDH cleared a backlog of results from two different laboratories. The state came under significant fire for lumping antibody and PCR test results earlier in the pandemic, and for changing its methodology for reporting results, which appeared to increase numbers.

On Friday, the state also erroneously reported the death of a child from COVID-19 for the second time.

Officials have been dealing with ever-increasing data as the pandemic continues and testing numbers rise after an initially sluggish start (the state’s percent positivity rate has hovered around 7 percent since mid-July, which indicates that case numbers are increasing faster than the growth in testing). 

This week, though, the state’s daily testing numbers have been significantly lower than its previous high of more than 20,000 results on July 24.

The highest daily number of tests in August was 14,165. On Tuesday, the state only recorded 8,449 testing encounters. Many local health departments organize their own community testing events, which contribute significantly to the state’s daily totals. Reppas said VDH was aware of two events that were postponed this week due to Hurricane Isaias: one in Portsmouth and one in Richmond.

Petri said that lower testing numbers could significantly affect the state’s recorded number of cases.

“A lot of those testing events are reaching populations that don’t have great access to medical care otherwise and that are at higher risk of infection,” he added. “So, if you lose testing numbers, that’s going to affect the case reporting pretty dramatically.”