Chicago Invasive Meningococcal Disease Outbreak Reaches 10 Cases and 2 Fatalities: Vaccinations Urged

The Chicago Department of Public Health (CDPH) is currently monitoring a cluster of invasive meningococcal disease (IMD) cases.

Since January 15, 2026, ten adult cases and two related fatalities have been confirmed.

As of mid-February 2026, this Chicago outbreak is primarily affecting the West Side and Southwest Side of the city, with case numbers far exceeding the typical 0-2 cases reported in January over the past decade.

All tested isolates from this outbreak are identified as serogroup Y, which has been the dominant strain in Chicago since 2022.

CDPH recommends the MenACWY vaccination (Menveo, MenQuadfi) for individuals experiencing homelessness and encourages hospitals to vaccinate at-risk patients upon discharge.

Nationwide, IMD cases have been increasing sharply since 2021. In 2024, there were 503 confirmed and probable cases (based on preliminary data), marking the highest annual total since 2013.

According to CDPH, Neisseria meningitidis, the bacteria that cause IMD, is transmitted through direct contact with saliva. However, it typically requires close and prolonged contact to spread.

For the most accurate and up-to-date national figures, please visit the CDC's meningococcal disease surveillance webpage.