Two years into the pandemic, the Oklahoma State Department of Health has changed how it calculates its seven-day average of new COVID-19 cases, dramatically reducing the numbers reported from what they would have been under the previous methodology.
The seven-day average would be 373 per day as of Thursday if the method used for calculations during the past two years were still used. But using the state's new method, the average was reported Thursday as 95.
Previously the State Health Department's seven-day average was based on all positive test results received during the previous seven days, regardless of when the test was done. Under the new methodology, only cases where both testing was performed and results were received within that same seven-day period are used to determine the average.
So positive COVID tests that are delayed in reaching the Health Department now don't count in the seven-day averages.
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That might make it seem that those lagging numbers are unaccounted for, but the Health Department does keep track of all positive test results received and still reports the cumulative total of positive cases in Oklahoma. The Tulsa World determined the seven-day average under the old methodology by subtracting last week's cumulative case total from this week's and dividing that number by seven.
Dr. Dale Bratzler, the University of Oklahoma’s chief COVID officer and one of many health leaders who have regularly dispensed important information to the public about the pandemic’s evolution, said the new methodology presents "most assuredly … an underestimate of the true number" of new daily cases.
"I think that the actual number of new cases per day is probably somewhere in between the number that I come up with using the consistent methodology and only looking at cumulative cases and the number that they're using now that reports only on tests reported in that past week."
Erica Rankin-Riley, a State Health Department spokesperson, said the new method will "slightly under-report" the average but is "more accurate" than using cumulative figures. She acknowledged that at-home COVID tests already go unaccounted for in state data.
Dr. Mary Clarke, president of the Oklahoma State Medical Association, said her group is "a little disappointed" that the state is switching to a method that substantially lowers its new case average.
To make it seem as if COVID is over is a disservice to patients down the road when another variant is expected to come through at some point, Clarke said. She said the change is providing a degree of a false sense of security when the state isn't yet out of the woods.
"If we accidentally overcounted those cases, then that's fine," Clarke said. "But what's happening is we're undercounting cases and looking like we're doing better than we are — and that's not fine."
The State Health Department's change comes at the same time it has shifted to reporting COVID data only on a weekly basis instead of daily.
Rankin-Riley said the widespread availability of home tests means positive cases are missing from state numbers, which is why the State Health Department and the Centers for Disease Control and Prevention are putting more focus on hospitalizations and surveillance systems.
"As with all attempts to report real-time COVID data, there is no perfect system," Rankin-Riley wrote in response to questions. "Delayed reporting from multiple sources will always limit our ability to provide perfect data. However, this method is a much closer approximation of the current reality."
The state's most recent number of weekly cases per 100,000 residents was 59 per day, which was tied for 22nd in the U.S., according to federal data. The case rate hasn't been that low since July — and the lowest was 15 per 100,000 per day in May.
The state's recent three-day average of COVID hospitalizations released Thursday was 262, with 65 — or 25% — in intensive-care units. The overall number is down 51% from 530 two weeks ago and down 88% from the record 2,243 inpatients posted Jan. 28.
COVID hospitalizations haven't been this low in Oklahoma since July, when the delta variant began spreading. The lowest COVID hospitalizations have been since the outset was 106, reported June 10.
The three-day average of Tulsa County COVID hospitalizations was 74 Thursday, with 30, or 41%, in ICUs. The county is down 50% from 148 two weeks ago and down 86% from its record 548 reported Jan. 29.
Bratzler said epidemiological models show that case counts might go up some — and might be already a bit — but that experts aren't expecting a huge surge, as happened with the delta and omicron variants.
"The one unknown variable always is: Will there be a new variant that evades the protection you get from a previous infection or from being vaccinated?" Bratzler said.
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