April 15, 2020

Mayor Lightfoot and CDPH Announce New Data Showing Chicago Is Starting to Flatten the Curve of Covid-19

New data shows rate of new COVID-19 cases begins to slow; suggests social distancing is effective in mitigating virus transmission in Chicago
Mayor's Press Office    312.744.3334

CHICAGO – Mayor Lori E. Lightfoot and the Chicago Department of Public Health (CDPH) today announced new data suggesting social distancing and the state’s Stay-at-Home order may be working to flatten the COVID-19 curve in Chicago, slowing the rate of increase in total cases in Chicago. This includes new case-level analysis gathered over the past month signaling great improvement in the time it is taking for the number of cases to double. Just one month ago, cases in Chicago were doubling every 2-3 days; now they are doubling only every 12 days.   

As Chicagoans approach the fourth week of the ‘Stay at Home’ order, this new data capturing cases, community mobility, as well as trends showing the consistent capacity of the hospital system, suggest the City’s mitigation efforts have been effective in reducing transmission of COVID-19. However, a steady decline in new cases still needs to occur before major social distancing interventions are no longer required. All data are available in a newly published data suite, shared on the city’s website Chicago.gov/coronavirus.

“Thanks to our citywide efforts to stay home and socially isolate, we have made important progress in flattening the curve and stemming the spread of COVID-19 in Chicago,” said Mayor Lightfoot. “However, as encouraging as these numbers are, the light at the end of the tunnel is only a pinprick and we will need continued diligence and social compliance before we can bend the curve and outrun this crisis. That’s why it is imperative we continue to be safe and act responsibly, as it is truly a matter of life and death.”

Flattening the curve means that Chicago has seen continuous progress in its effort to slow the spread of the virus, and therefore, protect the local healthcare system from becoming overwhelmed. The curve refers to the infection rate which, without interventions like staying at home, skyrockets to the peak and rapidly diminishes the capacity of local hospitals. As Chicagoans flatten the curve, the rate of increase of new infections begins to decline, where the number of people being diagnosed each day is still rising but at a slower rate. Flattening the curve allows the City to maintain resources, continue treating patients and ultimately, save lives.

“This data is encouraging and shows that all of our efforts appear to be having the intended impact in helping to limit the spread of this virus,” said Dr. Allison Arwady, CDPH Commissioner. “I want to thank the people of Chicago who absolutely have saved lives by staying home. But I want to be clear: this also tells us that we need to be abiding by these restrictions more now than ever, because we haven’t yet gotten to the other side of the curve, where the number of daily cases begins to fall day after day. We need to get to the other side of the curve to be able to move forward as a city.”   

The new suite of data published online today demonstrates that several factors contributed to the curve flattening, including orders that limited the size of gatherings, closed schools, prevented sick people from leaving home, and instructed all residents to stay home unless it is essential, along with the subsequent enforcement of these orders. The city also showed new data demonstrating a decrease in community mobility as measured by anonymous mobile device movement—more people actually staying home across Chicago—and explained that data like this can be used when restrictions eventually begin to be lifted to track the impact of these changes in near-real-time.

The new data confirms that policy decisions at the city and state level have positioned Chicago well for the next phase of the pandemic. Key take-aways include:

  • New case rate slowdown: The data show that the rate of increase of new COVID-19 cases has considerably slowed and that Chicago is making real progress in flattening the curve – cases were increasing by 25% to 50%per day just one month ago and are increasing by 8 percent per day now. This is best seen in the ‘days-to-doubling’ case numbers, with cases in Chicago residents doubling as quickly as every 1-2 days at the beginning of our local outbreak, as compared to every 12 days now.
  • Lower rate of cases and deaths: Data analysis shows Chicago could have had several times more deaths than currently have been reported if there hadn’t been a stay-at-home order and strong compliance with social distancing. Without such measures, modeling shows that the city could have seen more than 62,000 cases and 2,000 deaths by this point. 
  • Sustained hospital capacity: Chicago’s healthcare and hospital systems still have available bed capacity, ICU capacity, and ventilator capacity, indicating that the progress in flattening the curve has protected our health system so far.
  • Increased social compliance: New data from BlueDot, a health data company that shares data with CDPH, shows major improvement in Chicagoans staying at or near their homes since the orders were implemented last month. BlueDot metrics are derived from anonymous data linked to cell phone and mobile device movement, with location check-ins every 30 minutes. In February and early March, these metrics showed an average (median) of between 59% and 64% of phone check-ins in Chicago were at home, recognizing that we spend a lot of time at home, much of it sleeping. By last week, across Chicago, the average (median) phone check-ins at home had increased to 79% of all check-ins. No personal or individual data is reported.


While the City has seen this initial progress, it has also worked to greatly expand the capacity of its full system of care. City and healthcare officials, in conjunction with state and federal partners, worked proactively to provide additional capacity, should the hospitals become overwhelmed, with the construction of the McCormick Place Alternate Care Facility. In recent weeks, the City has also established new dedicated quarantine and isolation sites, adding 2,600 rooms, worked closely with city partners to reduce transmission in congregate settings, and transferred hundreds of residents experiencing homelessness to shelter settings where they can receive care and social distance while allowing the city’s existing shelter system to decompress. 

While data shows continued improvements, the City remains concerned about the prevalence of COVID-19 in Black and Brown communities, which have been disproportionately impacted in terms of sickness and death – with seven times the death rate when compared to white communities. Guided by the data, the City has developed a hyper-focused strategy centered around deep, consistent education, outreach, and intervention with communities most adversely impacted by COVID-19. Through a partnership with West Side United, the City’s racial equity rapid response teams will work to reach vulnerable populations in the communities most impacted by COVID-19, connecting them with resources and care to improve equity in health outcomes across the city.
 
As the City works to see a decline in new cases and to prepare for a “deceleration” phase, CDPH will continue to monitor a series of metrics, taking the following steps before a recommendation is made to exit the Stay at Home phase of the pandemic. This includes close tracking of new cases and deaths; monitoring local hospital capacity; working to increase testing capacity; leveraging new technologies and tools to monitor confirmed cases and conduct contact tracing; and continuing to reinforce compliance with social distancing requirements and the statewide mandate.
 
In response to the COVID-19 pandemic, the City launched the Stay Home, Save Lives campaign to inform residents about how they can stay healthy and do their part to bend the curve of the virus. For more information and updates on COVID-19, text COVID19 to 78015, email coronavirus@chicago.gov or visit Chicago.gov/coronavirus.

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