As Kate Brown moves to reopen Oregon, modeling warns of hazards ahead
As Gov. Kate Brown further reopens the economy, her administration's COVID-19 modelers have reported that generally relaxing social distancing could result in as much as a five-fold increase in hospitalizations in Oregon each day.
The state in press releases has repeatedly cited earlier work for Oregon by the Bellevue nonprofit Institute for Disease Modeling.
No press release accompanied the group's May 7 report, titled "COVID-19 trends in Oregon: Preparing for opening up."
Pandemic modeling accuracy has been hotly debated over the last two months. The May 7 report done for state officials, which has not been publicly discussed previously, is significant because of its timing and because it explicitly contemplates how the disease could spread under reopening in Oregon, more so than previous versions of the institute's work.
Brown has portrayed her efforts to reopen the state as careful and targeted, intended to help people and partially resuscitate the battered Oregon economy.
She already has relaxed the state ban on nonurgent medical and dental procedures. She now is relaxing social distancing in counties that have not been hard-hit by the coronavirus. She has said boosting testing, as well as contact tracing of infected people, should allow the state to control the spread of coronavirus. On Thursday, May 14, she announced that 31 of Oregon's 36 counties will be allowed to start reopening.
Multnomah , Washington and Clackamas counties were not among the 28.
The May 7 report does not specifically model Brown's plans, and notes that more detailed modeling of reopening is underway. It notes the uncertainty of its numbers, and several unknowns. But it states that a partial relaxation of social distancing — even while boosting testing and contact tracing as Brown intends — could lead to hospitalizations tripling or quintupling on a daily basis by June 14, jumping from the current three hospitalizations per day statewide to between 10 and 17 per day.
"The Oregon model simulations suggest that the future outcomes remain very sensitive to policy changes and public adherence to physical distancing guidelines," wrote the report's authors.
Asked about the possibility of 30 to 80 additional deaths in the coming month at her May 14 press conference, Brown said that an increase in infections and deaths was an expected and unavoidable result of reopening. "I know this," she said.
Dropping from baseline
As previous versions have, the report estimates that individual behavior and government social distancing measures have cut the disease transmission rate in Oregon by 70% from its projected baseline of what it would have been otherwise. Combining equivalent measures with increased testing and contact tracing would continue that level of success, according to the report.
One blip in that contention? An expected reduction in new infections that the modelers had projected for the previous two weeks has not materialized. Instead, Oregon's rate remained steady. That could reflect increased testing, or that the model's assumptions needed tweaking, according to the report.
Regardless, relaxing social distancing — even combined with increased testing and tracing — would lead to the reduction of transmissions to drop to either 60% or 50% below the baseline, according to the report. It projects those two scenarios to model the potential increase in infections.
The report does not translate its figures into deaths, but estimates that the two scenarios for relaxed social distancing would increase the cumulative number of people infected in Oregon by a combined 2,400 to 6,200 cases by June 14. The report assumes that 2.1% of those will be admitted to a hospital intensive care unit. According to a mortality rate assumption cited in the report, 1.3% would die.
Combining the infection projections with the report's cited mortality assumption indicates relaxing social distancing could produce between 30 and 80 additional deaths in Oregon by June 14.
The study that produced the 1.3% figure, however, has been controversial, and some have criticized that mortality rate as exaggerated.
Institute often cited
Authors of the Oregon modeling done by the institute did not respond to a recent Portland Tribune request to discuss their assumptions.
The Institute for Disease Modeling is part of the Global Good Fund, an effort backed by Bill and Melinda Gates. It has worked closely with the state since March 25, when the state agreed to share data in exchange for modeling. The institute has provided similar modeling to Washington state and other states. In Washington, the institute has warned that people are relaxing their personal social distancing efforts due to quarantine fatigue.
IDM's work was featured prominently in state press releases on March 26, April 1, April 11 and April 24. Its two most recent weekly reports, however, were posted without public notice on an Oregon Health Authority website with COVID-19 resources for "healthcare partners." Another report is expected by tomorrow.
The Brown administration has often cited the group's conclusions to support her earlier social distancing policies. As State Epidemiologist Dean Sidleinger was quoted as saying in an April 24 press release, "Our modeling continues to show that our collective efforts are working."
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