Weekly Surveillance Summary

updated:

1/3/2025

Key Points

• Overall acute respiratory illness activity level is HIGH across Chicago. Flu and RSV levels are particularly elevated, and COVID-19 continues to increase.  
• The first pediatric influenza death in Chicago of the 2024-25 season was reported this week. 
• The percentage of ED visits for flu has more than doubled since last week, surpassing last year’s peak; ICU admissions for flu are also rapidly increasing. ED visits for RSV remain very high, especially among children <5 years, and those for COVID-19 continue to increase modestly across all ages. 
• The percentage of specimens that tested positive for flu has increased substantially. Almost all (99%) flu specimens that were typed are flu A; among those subtyped, about half (54%) have been H1N1. Test positivity for RSV remains elevated, likely at or near the season’s peak. Test positivity for COVID-19 continues to increase modestly.
• Wastewater data is unavailable for week of Dec 22–28, 2024, but during the last week of available data concentrations of flu, RSV, and the COVID-19 virus were all increasing.  
• Flu and COVID-19 vaccine coverage across the city remain low. There is still time to get vaccinated! Other ways to protect yourself can be found here and here.
• For information on the national bird flu outbreak, see H5 Bird Flu: Current Situation.