Missing Social-Distancing Data Delays Modeling for COVID-19 Hospital Surge

JON HURDLE | MARCH 30, 2020

NJ Spotlight

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New Jersey hasn’t yet been able to model an anticipated surge in demand for hospital capacity for COVID-19 patients because it doesn’t have data on the effects of social distancing, but there are signs that hospitals will be able to cope, according to the state’s Commissioner of Health, Judith Persichilli.

The state’s health officials have been using CHIME, a tool for COVID-19 hospital capacity planning, which Penn Medicine at the University of Pennsylvania issued in mid-March. The tool, which has been made available to health care providers in 150 countries via open-source software, allows users to input data including the percentage of infected patients who have been hospitalized; the number of patients currently hospitalized, and the population a hospital system serves.

The resulting model also relies on the degree to which social distancing has reduced social contact, and that data wasn’t yet available, Persichilli said at Gov. Phil Murphy’s Friday briefing on the pandemic.

Because it’s taking up to a week to obtain the results of positive tests in the accelerating health crisis, those people may have been infected before the governor issued his executive order on social distancing on March 21, and so it’s not immediately possible to judge how effective the order has been, Persichilli said.

“It does not take into account our social distancing interventions, so any projection at this point in time is suffering from the lack of that information,” she said.

Anticipating higher demand for beds by mid-April

On the basis of limited information, Persichilli said she anticipates an increase in demand for COVID-19 critical-care hospital beds by mid-April. But she expressed confidence that hospitals will be able to cope. She said she had received assurances from the CEOs of three large hospital systems that they would be able to comply with her request to double their capacity.

“We believe we will be fine handling the critical-care surge. Three of our CEOs from the larger systems are prepared for that,” she said. “That will hopefully be in a couple of weeks so we can deal with it.”

As of last Thursday, 1,080 people were hospitalized for COVID-19, and another 8,172 people were awaiting test results, Persichilli said. As of Saturday, public and commercial laboratories had done 29,822 tests and found 10,436 positive cases, a positivity rate of 34.99%, she said.

Latest numbers

By early afternoon Sunday, the total number of positive cases in New Jersey had risen to 13,386, with 161 deaths and 22,216 negative test results, according to state Department of Health data.

Last week, Persichilli announced plans to add 2,360 hospital beds to the state’s inventory. The additions would include 1,000 beds in four field hospitals being built by the U.S. Army Corps of Engineers; several hundred beds at the reopened Inspira Medical Center in Woodbury, and reopening unused wings of other hospitals.

The new beds would be for general medical/surgical patients, with the exception of 500 beds at the NJ Convention Center at Edison, which will be for COVID-19 patients only, according to Donna Leusner, a DOH spokeswoman.

On Friday, Persichilli said she’s still looking at what effect social distancing is having on “flattening the curve” — or reducing the height of the projected peak in hospitalizations so that hospitals won’t be overwhelmed when it occurs — the overarching goal of officials who are trying to manage the pandemic.

They hope that by persuading people to stay at home except for essential trips out, and by staying at least 6 feet away from anyone they meet, they will be able to slow the growth in infections to the point where it matches hospital capacity.

“Social distancing is the only tool we have in our tool kit,” Persichilli said. “It reduces the transmission of the disease, it reduces the risk in cases and flattens out the number of hospitalizations at any one time. Flattening the curve will protect vital health resources such as beds, personal protective equipment and medical devices. It will also reduce the impact overall of COVID-19 on our residents.”

Governor orders daily reporting of data

On Saturday, Murphy issued an executive order directing all health care facilities to report daily data on their capacity to respond to COVID-19 cases, such as the number of beds and ventilators and stocks of personal protective equipment for staff. Facilities including acute care hospitals and long-term care facilities are required to send the data to the state’s Office of Emergency Management by 10 a.m. each day, starting Sunday.

“Today’s executive order will allow us to more efficiently and effectively manage the flow of personal protective equipment as hospitals begin expanding their capacities to meet the need of more COVID-19 patients, and allow us to have constantly up-to-date data on bed capacity throughout the State,” Murphy said.

He also issued a statement saying that “frontline” workers, such as those in health care and food supply, should continue their duties. The statement followed one from the Centers for Disease Control and Prevention on Saturday that urged residents of New Jersey, New York and Connecticut to avoid non-essential domestic travel for 14 days.

“If you have been working as part of our frontline response effort, from health care workers to supermarket workers, we still need you on the job,” Murphy said.

To anticipate a surge in infected patients, the CHIME tool, which stands for COVID-19 Hospital Impact Model for Epidemics, allows users to predict COVID-19 hospital demand based on local characteristics. To illustrate, the Penn Medicine researchers used Pennsylvania’s policies such as school closings and social distancing. They estimated that cutting the number of daily interpersonal contacts by 30% would result in a 65% reduction in the demand for critical-care beds at the peak of the curve compared with a “do-nothing” scenario.

Two models are consistent

The tool’s projections are consistent with a recent model for Britain and the United States from Imperial College in London, which projected reductions in demand for critical-care beds, depending on successively tighter quarantine policies.

The number of beds needed drops from about 275 per 100,000 population by mid-May if policymakers enacted no quarantining policies to less than 100 by early June if infections are isolated, schools and universities are closed, and households and seniors are quarantined, that model indicates.

In the U.S., a “do-nothing” scenario would result in demand of 730,000 critical-care beds, or 7.5 times the national number available, according to the Imperial College paper. It also projected that, without mitigation, the pandemic would kill 2.2 million people in the U.S. by early July.

Michael Draugelis, chief data scientist at Penn Medicine, said the consistency of the two models indicates that they will help users such as New Jersey anticipate a surge in COVID-19 patients, and build a model based on local characteristics.

“Our tool allows analysts who work in any of these groups to pull in the characteristics that are observable from reported known infections to how many people are hospitalized in your hospital now, to understand where you are in this surge and how much the curve is being flattened by state policies,” he said, in an interview with NJ Spotlight.

However successful policymakers may be in “flattening the curve,” it’s clear there won’t be an early end to the pandemic, Murphy said on Saturday.

“I don’t see any scenario where this doesn’t bleed meaningfully into May,” he said. “I hope I’m wrong about that, and if I am wrong, I’ll be the happiest guy in New Jersey, if not America.”

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