Things are looking better to those of us who track the rise and fall of COVID-19 cases in earnest.
Daily confirmed case counts, hospitalizations and deaths have all dropped since spiking in July. The percentage of positive test results, averaged over a week, stood at about 3.3% in early September. That figure spiked to nearly 6% in mid-July, according to state data. The state’s goal is 2%.
“We are pleased to see the testing positivity rate come down. We know the number of cases are decreasing across the state,” said Dr. Cathy Wasserman, a state epidemiologist with the Department of Health (DOH), who added that people must remain vigilant, keep their distance and avoid gatherings. “Human behavior is driving transmission changes.”
No single behavior change likely accounts for the reduction in transmission. Instead, the health department attributes the improvement to a combination of factors such as wearing face coverings, limiting social gatherings and keeping physical distance in public. Gov. Jay Inslee required people to wear face coverings in public starting on June 26, as cases trended higher.
The encouraging drop in the state’s positivity rate is one sign transmission is slowing, but perhaps more importantly, the figure indicates that statewide testing is keeping up with the rate of the virus’s spread.
The health department also is counting tests differently. The department in late August made several tweaks to its reporting of COVID-19 data and applied them retroactively. It was the latest in a series of adjustments to its methodology that the agency hopes will give a more accurate picture of the virus’s presence in Washington.
Because some people are getting tested multiple times, the state is now counting the number of tests administered rather then the number of people tested.
“We feel that is a more accurate representation of testing volume,” said Wasserman, who is leading the health department’s COVID-19 data efforts. The change will also help standardize Washington data for comparison with other states, she said.
Counting tests this way dropped the state’s overall, all-time positivity rate (the percentage of all tests in Washington that have come back positive). But, as the pandemic wears on, that figure has become less important. Instead, the health department highlights a seven-day average positivity rate, which makes it easier to spot changes and trends.
Since the pandemic began, the task of compiling COVID-19 data has been beset with problems as health departments nationwide scrambled to tweak health reporting systems to handle all the metrics needed to track the new virus. In Washington, an initial flood of data overwhelmed the state’s disease reporting system, and then, a computer workaround caused the state to double-count negative test results for two months. Those problems, and several others, have been corrected.
Washington state also has added to its COVID-19 data dashboard a new metric — testing per capita — which will help officials examine and compare people’s access to testing across geographic areas.
And on Aug. 28, the state stopped reporting deaths from COVID-19 on weekends.
“We made that decision due to resource challenges at the state and local level. Many medical certifiers and public health officials we need to reconcile the count don’t work on the weekends,” Wasserman said.
Dealing with resource constraints has been a theme at the DOH. The pandemic’s magnitude has forced the department to reshape its data systems. Wasserman said the agency is currently processing “more labs in one day from COVID-19 than we were previously processing in a month” for other conditions.
Other states and nations have been no less bewildered by the challenge. Many have rejiggered data. Auditors in 11 U.S. states are now examining how public health officials compile and track data (Washington isn’t among them).
“Everything that is happening that you’ve seen with the Washington state Department of Health is repeated all over the world,” said David Pigott, an assistant professor at the Institute for Health Metrics and Evaluation (IHME) at the University of Washington School of Medicine, who works on data intake from all over the world. “These different data systems are being stressed in a totally unprecedented way — the demand for the frequency of information and the detail of information is something I’ve never seen really required before.”
Pigott said it will be essential — once COVID-19 was “settled down” — to interrogate the systemic problems with data systems worldwide and make pre-emptive changes before the next pandemic so coordination between health departments is easier.
