Georgia’s COVID-19 positive rate is higher than what state reports. Here’s why.
Georgia has performed more than 400,000 coronavirus tests since the beginning of the pandemic, and the state health department reported more than 50,000 new tests over the weekend — the highest two-day total since the state’s first cases were confirmed.
Nearly 800 tested positive for the novel coronavirus.
But some of these tests aren’t meant to find those currently sick, a practice that public health experts say artificially raises Georgia’s testing totals and artificially lowers the state’s percentage of positive tests.
A representative for the Georgia Department of Public Health confirmed Monday that data on its website listing the total number of tests performed includes both antibody and viral tests for the novel coronavirus. The two tests are not the same. Antibody tests tell signs of previous infections while viral tests identify those who are currently infected.
“You’re putting apples and oranges together and calling them oranges,” said Dr. Harry J. Heiman, a clinical associate professor at Georgia State University’s School of Public Health. “You’re mixing two different tests. ...All that does is over-inflate the testing number.
“If anything, it skews those numbers to make it appear like the level of disease relative to testing is actually dropping much more dramatically than it is.”
The acknowledgment comes as Gov. Brian Kemp and other state officials have touted the state’s expanded testing and the declining rate of positive cases over the past several weeks as Georgia works to fight the spread of COVID-19.
Nancy Nydam, a spokesperson for the Georgia health department, said the state received its first antibody test results on April 16.
But it’s unclear how much of the state’s recent testing increases can be attributed to antibody testing. Nydam was unable to provide McClatchy with the number of total antibody tests performed in Georgia since mid-April.
Antibody testing and Georgia totals
Antibody testing for SARS-CoV-2, the virus that causes COVID-19, searches for the presence of antibodies, the specific proteins made in response to infections.
The antibodies can be found in blood and are important for identifying previous infections in people who had few or no symptoms. A positive antibody test means that you likely had a COVID-19 infection, the CDC reports.
In Georgia, residents tested for antibodies will be counted among the state’s total number of coronavirus tests, Nydam said.
But a positive antibody test by itself will not be added to the state’s list of confirmed cases. Instead, those who test positive for only the antibodies will be listed by state officials as a probable case, said Nydam, who cited guidance from the CDC.
Testing numbers reported by the Georgia Department of Public Health have increased overall but fluctuate day-to-day. McClatchy calculates the number of tests reported each day by subtracting the number of tests reported on the current day as of 7 p.m. from the number of tests reported on the previous day at 7 p.m.
As of May 19, Georgia’s positive test rate is nearly 10.2%, down from over 16% at the start of May. But it’s unclear how much antibody testing has influenced the increasing number of tests performed and the declining percentage of positive tests in the state.
Information listing the number of positive or negative antibody tests is not published on the state’s website.
“As the number of serology tests in Georgia is growing, DPH’s data team is working with our epidemiologists to account for this data in an accurate and clear presentation,” Nydam said.
Heiman, the Georgia State professor, said the state should report its antibody testing separately. Some states, like Arizona, are currently doing this.
“That would give us useful information in terms of the number of people who are showing immunity to COVID-19,” he said. “But when you mix the two together, it really just clouds the picture and makes the data much less usable for people trying to track the epidemic in a meaningful way.”
Georgia is not the only state that added antibody tests to its total testing numbers. Virginia discontinued the practice last week after critics said it exaggerated the state’s response to stopping the spread of the virus, the Washington Post reports.
In Virginia, antibody tests had amounted to less than 9% of the state’s overall testing for the coronavirus. Texas is combining some of its antibody testing into its statewide testing data, the Texas Observer magazine reported.
More on Georgia COVID-19 testing
Of the more than 400,000 tests recorded by the Georgia Department of Public Health, more than 335,000 were reported after April 16.
During that time, the state eased some of its coronavirus restrictions by ending a shelter in place order except for its most medically fragile residents and allowing some previously shuttered businesses to reopen. The state expanded coronavirus testing to all Georgians, even those without symptoms.
Georgia is seeing improvements in some of its coronavirus metrics.
Data from the Georgia Emergency Management and Homeland Security Agency shows 959 residents with confirmed COVID-19 cases are currently hospitalized as of May 20, representing the lowest total since early April. The COVID Mapping Project reports Georgia is 21st in testing per capita in the country.
Georgia’s seven-day average for newly reported cases is around 611 as of May 18, a decrease of nearly 40 cases since last week, based on raw case numbers analyzed by McClatchy.
“Our focus on increased testing is yielding strong results as the Georgia National Guard, Georgia Department of Public Health and various public and private-sector partners continue to work non-stop to improve access to COVID-19 testing for Georgians,” Kemp said in a news release Monday. “We are working tirelessly to move the needle on testing as we take measured steps to safely reopen the Peach State.”
A recent change to Georgia’s test reporting policy might also be affecting the percentage of positive tests for more recent days.
As of May 4, state health officials are now requiring all labs and medical facilities to report negative tests to the Georgia Department of Public Health.
Since the May 4 change, state health officials have logged 12,909 total test results for samples collected prior to May 1, Nydam said. It’s unclear if all or just a portion of those tests were negative. The Georgia Department of Public Health had not previously acknowledged some negative test results weren’t being reported until Gov. Kemp told reporters last week.
“Many hospitals that test in-house were and are only reporting positive test results to us. We recently modified our notifiable disease requirements to encourage more hospitals to electronically report all COVID-19 tests that they perform and are actively reaching out to them to advise them of the reporting requirement,” Nydam said. “Nearly half of these were due to the onboarding of two new labs that were new to working with DPH and with whom we had been working around two weeks to establish electronic reporting.”
Georgia currently does not provide historical data or a list of dates when coronavirus tests samples were taken, possibly further clouding the true number of coronavirus tests performed in recent days, Heiman said.
“It makes us look like we’re doing a more significant ramp-up in a short period of time that we are,” Heiman said. “For people looking at trendlines in the data … it just continues to skew the results.”
Why does this matter?
State politicians, public health experts and those tracking Georgia’s coronavirus trends have criticized the state for errors with data and charts over the past several weeks.
On its website that explains the data it reports, Georgia health officials do not indicate antibody testing is included in the total testing count. Nor did officials say that some labs or medical facilities were not reporting negative tests.
Issues like these “continue to erode the credibility that the Department of Public Health has as an honest broker of reporting test results,” Heiman said.
“What we have is a continuing process of having to make adaptations to the reporting because of logistical challenges — some with the Department of Public Health, but some with partners that are doing testing — without any transparency about changes that are being made,” he said. “This is not the first time, not the second time, not the third but the fifth or sixth time that you have failed to appropriately communicate what you are doing.”
This story was originally published May 20, 2020 at 5:50 AM.