Early data show that cities with mask mandates are finding success in tamping down the spread of COVID-19 in Oklahoma, according to OU-Tulsa’s chair of medical informatics.
Dr. David Kendrick, who also is CEO of MyHealth Access Network, compared test positivity rates — the percentage of COVID-19 tests performed that are positive — in cities with mask policies against the rates in cities that don’t require masks in public. There was a 4.4% drop in positivity rate for masked municipalities compared to unmasked ones 21 days after each city implemented its face-covering requirement.
Kendrick said he wasn’t necessarily surprised when he saw the data but was more curious about whether data would show an effect that soon.
“OK, that confirms what we thought might be the case,” Kendrick said of his research. “But I would say probably a lot of people will be surprised by these results.”
Kendrick shared his findings Wednesday afternoon with journalists in a livestream on YouTube. The positivity rates are based on seven-day rolling averages, with Kendrick later updating the data to be current as of 6 p.m.
The cities with face-covering policies represent 1.3 million people of Oklahoma’s 4 million residents, meaning the population in communities and rural areas without such a mandate is 2.7 million.
Tulsa’s positivity rate compared to that in all cities without mask mandates dropped 4.3% after three weeks of its order being in place, according to MyHealth data.
Tulsa’s positivity rate sits at 10.2%, while all cities with mask orders combined is 9.2%, according to MyHealth data. Kendrick described those rates as remarkable because most cities that implemented mask orders started with positivity rates at 16% to 17%.
Kendrick noted that most public-health experts consider a positivity rate above 10% to be bad. Below 5% is a good level, he said.
“If you’ve got a couple of weeks at below 5%, then you’re in fairly good shape as a community,” Kendrick said.
Oklahoma’s overall positivity rate since July has bounced each week between 8.9% and 10.4%, with the most recent week being 9%, according to the state epidemiologist’s weekly reports.
Kendrick said he chose to use the positivity rate rather than daily new cases because positivity is less sensitive to reductions in testing.
“So positivity is a very useful metric when you are not confident that everybody in the community is able to be tested, which I think is the situation we’re in here in Oklahoma,” he said.
He also pointed to a study in the August edition of Health Affairs, which found that states mandating the use of face masks in public had a greater decline in daily COVID-19 growth rates after issuing the orders than did states that didn’t impose face covers.
Kendrick is encouraging either the state or local governments to establish a data point at which mask mandates could be relaxed in Oklahoma rather than leaving elected leaders to rely on emotions.
He said doing so would help “remove some of the politics” from the discussion and incentivize people to try to meet the measurable target. Perhaps it would even engender good-natured competition among cities, he said.
“Obviously, everything is subject to new evidence coming along, but a hospital metric, positivity rate below 5% for a couple weeks, could be an indicator,” Kendrick said. “There could be others.”
He offered another positive development.
The average testing delays grew “exorbitantly” in the previous four to five weeks, with one week even surpassing 100 hours — or four-plus days — for an average test turnaround time.
However, Kendrick said, the past week’s average of a 22-hour turnaround is the lowest yet.
“So that’s a good sign that our infrastructure is improving and that we’re going to be able to meet the needs here,” he said.
Interim Oklahoma Health Commissioner Lance Frye issued a public health advisory on Aug. 13 to speed up COVID-19 testing turnaround times.
The advisory called for public and private entities to increase capacity to do more tests and have all test results turned around within 48 hours or less.
In mid-July, the Oklahoma State Department of Health acknowledged that fax machines and manual data entry created challenges that led to inconsistencies in the movement of test data among health departments, clinics and laboratories.