The young adult female patient sits on the hospital bed and leans forward to look at the test results on the clipboard held by the mid adult female doctor.

Respiratory Illness Monitoring

Boulder County Respiratory Illness Data

Boulder County Public Health analyzes data to measure respiratory illness in Boulder County. This interactive tool provides an overview of emergency department (ED) visits and hospitalizations in Boulder County for respiratory illnesses, including Respiratory Syncytial Virus (RSV), Influenza-Like Illness (ILI)*, and COVID-19, during the respiratory illness season.

*ILI: A category of illnesses that share symptoms with influenza, such as fever, cough, and sore throat, but may be caused by various respiratory pathogens, including flu viruses.

This data is updated weekly on Mondays (Tuesdays during holidays) during the respiratory illness season.

Accessibility Disclaimer

This website contains materials from external parties that may not be fully accessible. To request an Americans with Disability Act (ADA) accommodation, please email ADA@bouldercounty.gov, or call 303-441-1386. View the county’s accessibility statement.

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Hospital Admissions

Respiratory Illness Hospitalizations

“Rate per 100,000 population” is calculated by dividing the number of hospitalizations by the total population and multiplying by 100,000, allowing easy comparisons across groups or time periods.

The red vertical line indicates a data lag. Data on the right side of the red line is preliminary due to reporting delays.

From January 2024 to June 2025, the highest percentage of hospitalizations for Influenza-Like Illness was 5.8% in January 2024.

Emergency Department Visits

Emergency Department Visits Data

The emergency department (ED) visit percentage is calculated by dividing the number of illness-specific ED visits by the total number of ED visits for the same period and then multiplying by 100. This highlights the relative impact of respiratory illnesses compared to all other ED visits.

During the 2025-2026 respiratory illness season, the peak of RSV hospitalizations occurred in August of 2025.

Vaccines

Vaccines are the most effective way to protect against flu, COVID, and RSV.

Find an immunization clinic near you.

Vaccines for Adults

During the flu season, adults can receive the vaccine at many locations throughout the county, including most pharmacies. Call the Colorado Department of Public Health & Environment at CO HELP at 1-877-462-2911 for locations, dates and times, costs, ages immunized, types of vaccines provided, types of insurance accepted, and if an appointment is required.

Vaccines for Children

Boulder County Public Health (BCPH) Immunization Clinics offer vaccines for clients who meet the following qualifications:

Medicaid for children
Section 317 Immunization Program
Vaccines for Children (VFC) Program

Learn More about Flu

Influenza (Flu) (CDC)