More than one year after the COVID-19 pandemic arrived in the United States it is still a part of our daily reality. Here is the latest data on the state of COVID-19 in Illinois and the Chicago area.
Health experts measure the impact of a pandemic by seeing how much the number of overall deaths has exceeded estimates based on historical trends. While non-coronavirus related deaths have been near predicted levels, thousands more have died in Illinois than expected since the pandemic reached the state.
Latinos in Chicago represent a disproportionate number of cases in the city, accounting for more than a third of cases even though they represent 29% of its population. Additionally, African-Americans made up about 32% of Chicago’s population as of 2010 but over 40% of people who die from COVID-19 related causes in the city are black.
These groups are not more susceptible to the virus than other groups, but rather they are being infected at a greater rate and are more likely to have co-morbidities like diabetes, hypertension and lung disease, and are dying at a greater rate as a result.
While the State of Illinois estimates around 98% of those diagnosed with COVID-19 recovered after 42 days, the disease has been deadly for many. The vast majority of those who ultimately die from COVID-19 (more than 90%) usually have at least one underlying chronic condition, such as diabetes, hypertension, or lung disease.
Data in Chicago mirrors statistics from around the world in showing that the number of cases of COVID-19 are spread relatively evenly among different age groups, but the virus is particularly deadly among older individuals and those with pre-existing health conditions.
Where data comes from and how to read it
Information on the latest COVID-19 tests, cases and deaths is reported to the State of Illinois by a wide range of entities including testing centers, hospitals, coroners and healthcare providers.
Each day, the state releases figures which include all the new reports they’ve received in the past 24 hours. This is why they’re referred to as “reported” cases, tests and deaths – they are not necessarily the number of cases, deaths or tests which occurred on a specific day, but rather the latest figures received by the state and then shared with the public.
Hospitalizations and deaths are considered “lagging indicators” of the spread of COVID-19, since it can take at least a week for someone to test positive after showing symptoms, two weeks for a case to grow serious enough to require hospitalization and three to six weeks for someone to pass away.
One exception is the daily positivity rates which are reported by the State of Illinois. Those rates are typically delayed by a few days in order to ensure that they’re accurate, and reflect the number of cases and total tests over that period.
It should also be noted that there is likely a significant number of people who have not been diagnosed with COVID-19 and recovered on their own, and as such are not reflected in the numbers. Overall, experts estimate 97% of people with confirmed cases have recovered as well.
Here are some ways to make sense of the data:
- 7-Day Average: Data fluctuates on a day-to-day basis so experts often look at these numbers over a “seven-day rolling average” to identify wider trends
- 14-Day Average: Things like holidays and backlogs at state offices can cause some spikes in the data, so looking over a longer time period provides a more conservative look at trends
- Case Positivity Rate: The percent of all COVID-19 tests performed which confirmed an individual with a new case of COVID-19, typically measured over a 7-day period
- “Flattening” the curve: When the 7-day averages of new infections stops rising
- “Probable” cases: COVID-19 tests confirmed by rapid saliva-based antigen tests as “probable” cases pursuant to CDC guidelines. These tests typically make up less than 10% of daily totals.
- Test Positivity Rate: Percent of all tests performed which came back positive, typically measured over a 7-day period.