Backlog of unreported negative COVID-19 test results floods VDH dashboard, lowering overall positivity rates

A backlog of negative COVID-19 test results flooded the Virginia Department of Health’s daily dashboard today, retroactively reducing the overall positivity percentages statewide and in Henrico.

In total, about 31,500 negative tests that were administered throughout the state during previous weeks are now reflected in the VDH’s daily tracking system for the first time. The results appear now because the two laboratories that processed them began electronic reporting to VDH this week, officials said.

The two labs had been reporting all positive results at the time they were processed, and those results were entered by hand into the agency’s system, VDH officials said. But the negative results had not been entered – meaning that statewide data showed a higher percentage of infection among those tested than actually was the case.

The exact number of back-dated negative test results in Henrico is unclear, but VDH data as of June 12 showed that more than 23,300 tests had been administered to county residents – an increase of more than 8,000 since Wednesday alone. (Typically, between 300 and 400 new tests are reported daily in the county.)

The new number of overall testing encounters in Henrico amounts to about 7 percent of the county’s population – up from the 4.6 percent originally believed to have been tested just three days ago.

The new data has altered – in a positive way – one of the most critical points of analysis about how, or if, the virus is spreading: the 7-day moving average of positive test results.

Though the graph illustrating that average for Henrico since the pandemic began follows relatively the same path it did before the new data was reflected – a peak during the first few weeks, followed by a steady decline, then several up-and-down weeks in May and relative stability in June – the percentages themselves largely have decreased across the board.

For example, just three days ago, data showed that the 7-day moving averages of June 6 in Henrico was 11.9 percent; today, that percentage dropped retroactively to 10.7 percent on the same day.

The 7-day moving average in Henrico is 10.2 percent today; statewide, it is 8 percent (down from nearly 9 percent three days ago).

For more than two months, the county’s peak in that 7-day moving average percentage was shown as having occurred April 4 (33.2 percent); today, the percentage shown for the same day is 24.7 percent, and the overall peak now is shown to have occurred on the second day for which test results were available, March 17 (35.8 percent).

The peak moving positivity percentage in May had been 15.6 percent, but the influx of the new data today lowered that retroactively to 12.6 percent.

In one apparent daily change, more than 2,000 testing encounters are now shown as having taken place May 8 in Henrico.