Questioned earlier this week about Virginia’s practice of sweeping still-questionable antibody tests into its total count of COVID-19 tests preformed, Gov. Ralph Northam’s administration claimed it was using the same methodology as several other states.
That’s not true, according to The Atlantic, which checked with the three jurisdictions the Department of Health said Virginia was following: Arizona, West Virginia and the District of Columbia.
“Virginia’s decision to mix the results of two different kinds of tests marks a new low in data standards,” the magazine wrote in an article headlined “How Virginia Juked Its COVID-19 Data.”
Virginia has been ranked among the lowest in the country for per-capita testing, and Northam’s chief of staff, Clark Mercer, grew visibly frustrated Monday when reporters questioned the decision to combine the two data points, arguing the state “[couldn’t] win” by separating the results.
Hours after the Atlantic published its report, the Virginia Department of Health released disaggregated data, but argued the separation made no real difference in closely-watched testing trends Northam has cited in his decision to begin reopening the state on Friday.
“Going forward the Virginia Department of Health will provide a breakdown of the COVID-19 test data by all test types and by only PCR tests,” the agency wrote in a press release, arguing the separation made no real difference in trends.
In a tweet on Wednesday, Northam wrote that VDH had been reporting results from PCR and antibody tests together since the beginning of the pandemic in Virginia. “When I found out recently that data from all types of tests were being combined, I immediately directed that the diagnostic tests be separated out,” he added.
.@VDHgov has been reporting all tests, regardless of the type of test, since the beginning of this health crisis. When I found out recently that data from all types of tests were being combined, I immediately directed that the diagnostic tests be separated out.
— Ralph Northam (@GovernorVA) May 14, 2020
Northam was present at the press conference on Monday when Mercer defended the administration’s decision to combine the two results. During the same briefing, Virginia Health Secretary Dr. Daniel Carey also said that the state added antibody test results later into the pandemic.
“We started with just the PCR tests and then that was the dominant test,” he said. “And serologic tests were added. They were added — again, the idea is to survey all the tests we could about this disease. And in retrospect, we may have chosen a different path. Without guidance, we went for as much testing as represented in the community.”
Antibody tests were not made widely available until several weeks into the pandemic. The FDA only recently lifted guidelines that limited that form of testing to certified laboratories.
VDH delayed in releasing the separated data for almost a week after the Richmond Times-Dispatch first reported that the department wasn’t separating PCR tests — currently the only reliable way to detect active infections of COVID-19 — from antibody tests, which only detect whether someone has been infected with the virus at any point in time.
While VDH wrote that the change in reporting made no substantial difference in the state’s metrics, it appears that antibody tests made up approximately nine percent of the state’s overall test results — a not-insignificant portion of the data.
And as the Times-Dispatch reported, the rollout of antibody tests for COVID-19 has been accompanied by scrutiny of their accuracy. “Only a handful have received Emergency Use Authorization from the Food and Drug Administration,” according to researchers at the University of California San Francisco and Berkeley.
The same report noted that while many performed “reasonably well, especially two weeks or more after infection,” “many of the test kits have false positive rates that may exceed the proportion of people who have been infected in some communities.”
As the Times-Dispatch reported, Dr. Denise Toney, the director of Virginia’s state lab in Richmond, has previously expressed reservations about antibody test results.
The change in reporting also pushes Virginia’s percent positivity rate — the percentage of COVID-19 tests that return positive — up one percentage point, to 15 percent.
Public health experts told the Mercury on Wednesday that 14 percent, the state’s previous percent positivity rate, was still significantly large for a pandemic situation, indicating that the risk of contracting the virus remains high. Researchers say that states should aim for a positivity rate of 10 percent or lower, which indicates that testing has become widespread enough to catch most infections in the community.