Chicago’s Department of Public Health has published five alerts in 2026 whose titles begin “Increase in Opioid Overdoses in Chicago” — on January 2, June 3, July 2, July 16 and September 2 — while its public alert file holds three such alerts from all its earlier years combined: two in 2020, whose titles use the singular “Overdose,” and one in 2025. Two more, in 2021 and 2024, announced an increase in opioid overdoses without naming a place. The file’s description calls the Health Alert Network the department’s channel to medical providers, laboratories, first responders and other partners; what the file records for each alert is the date it was published, not how many overdoses lay behind it.
Health Alert Network alerts (yfns-6ztj), 1,835 alerts dated October 11, 2017 through September 14, 2026, retrieved September 16, 2026; the file was last updated September 14, 2026 · published by the Chicago Department of Public Health as a convenience copy of its Health Alert Network site · counts use each alert’s date, title, topic, categories and priority; the alert texts were not read · an alert is not a count of illness or overdoses · no cause is assigned to any change · no medical advice is given hereFive alerts with the same opening words
| Date | Title, as filed | Topic label | Priority label | Grouped here as |
|---|---|---|---|---|
| August 31, 2018 | Informational Webinar: Understanding Opioid Overdose Reporting in the Hospital ED | Notification | Low | Other overdose title |
| January 3, 2020 | CDPH HAN: Acute Cannabis Intoxication/Overdose | Substance Abuse | Low | Other overdose title |
| June 5, 2020 | Increase in Opioid Overdose in Chicago | Opioid Concerns | Low | Increase, Chicago in the title |
| July 1, 2020 | Increase in Opioid Overdose in Chicago – June 30, 2020 | Opioid Concerns | Low | Increase, Chicago in the title |
| December 17, 2020 | Increase in Fatal Drug Overdoses Across the US Driven by Synthetic Opioids Before and During COVID19 | Opioid Concerns | Low | Other overdose title |
| December 31, 2020 | 2019 Chicago Opioid Overdose Data Brief | Opioid Concerns | Low | Other overdose title |
| June 30, 2021 | Increased Opioid Overdose Activity | Opioid Concerns | Low | Increase, no place in the title |
| July 2, 2021 | IDPH: Opioid Overdose Increase in West Chicago | Opioid Concerns | Low | Other overdose title |
| December 31, 2021 | 2020 Chicago Opioid Overdose Data Brief | Opioid Concerns | Low | Other overdose title |
| April 6, 2022 | Increase in Xylazine-related Overdose Deaths in Illinois | Substance Abuse | Low | Other overdose title |
| June 17, 2022 | IDPH: Overdose Clusters in Northern Illinois | Opioid Concerns | Medium | Other overdose title |
| December 9, 2022 | 48 Hour Opioid Overdose Reporting | Opioid Concerns | High | Other overdose title |
| May 14, 2024 | Increase in Opioid Overdoses May 14, 2024 | Opioid Concerns | High | Increase, no place in the title |
| November 8, 2024 | Overdose Cluster Associated with Nitazenes and the Novel Adulterant BTMPS November 8, 2024 | Opioid Concerns | High | Other overdose title |
| June 25, 2025 | Increase in Opioid Overdoses in Chicago | Opioid Concerns | High | Increase, Chicago in the title |
| January 2, 2026 | Increase in Opioid Overdoses in Chicago – January 2, 2026 | Opioid Concerns | High | Increase, Chicago in the title |
| June 3, 2026 | Increase in Opioid Overdoses in Chicago – June 3, 2026 | Substance Abuse | High | Increase, Chicago in the title |
| July 2, 2026 | Increase in Opioid Overdoses in Chicago – July 2, 2026 | Substance Abuse | High | Increase, Chicago in the title |
| July 16, 2026 | Increase in Opioid Overdoses in Chicago – July 16, 2026 | Substance Abuse | High | Increase, Chicago in the title |
| September 2, 2026 | Increase in Opioid Overdoses in Chicago – September 2, 2026 | Substance Abuse | High | Increase, Chicago in the title |
Four of this year’s five came in the 13 weeks from June 3 to September 2, two of them 14 days apart in July. No earlier 13-week stretch in the file holds more than two alerts announcing an increase in opioid overdoses. If the two that name no place — June 30, 2021 and May 14, 2024 — were also about Chicago, this year’s five would equal the earlier years’ total rather than exceed it; their titles do not say.
The labels moved as well. The January 2 alert is filed under the topic “Opioid Concerns,” like the three earlier alerts that begin the same way; the four since June 3 are filed under “Substance Abuse.” All five this year are marked High, the level the file’s priority note calls the default. Our reading: the file shows the department publishing this warning more often in 2026 than in any earlier year it holds. It does not record the overdose numbers behind any alert, so it cannot say whether that reflects more overdoses, a change in when the department publishes this alert, or both.
Fifty-eight topics, led by COVID-19 and flu
| Topic label, as filed | Alerts |
|---|---|
| COVID19 | 351 |
| Influenza | 340 |
| VFC | 125 |
| School Health | 103 |
| West Nile Virus | 102 |
| Announcement | 101 |
| STI | 67 |
| Respiratory Virus | 55 |
| Laboratory Information | 45 |
| Infectious Disease | 42 |
| Viral | 40 |
| Monkeypox | 39 |
| 46 other topic labels | 425 |
| All alerts | 1,835 |
COVID-19 and influenza labels account for 691 of the 1,835 alerts, 37.7 percent. A topic count is a count of labels, not of subjects: four of the five alerts marked Urgent in March 2020 are filed under “Viral,” and three of those four name COVID-19 in their titles. All 102 West Nile Virus alerts are dated June through October, the season of the mosquito-trap tests this desk tracks, and August has the most, 27. Influenza alerts run all year but are fewest in June, nine across the whole file.
Fewer alerts since 2021, until COVID-19 is set aside
| Year | Alerts in the file | Of them, topic COVID19 | Dated on or before September 14 |
|---|---|---|---|
| 2017 | 27 (from October 11) | 0 | 0 |
| 2018 | 135 | 0 | 93 |
| 2019 | 155 | 0 | 119 |
| 2020 | 229 | 87 | 155 |
| 2021 | 297 | 168 | 211 |
| 2022 | 261 | 62 | 170 |
| 2023 | 251 | 26 | 186 |
| 2024 | 213 | 4 | 158 |
| 2025 | 176 | 3 | 126 |
| 2026 | 91 (through September 14) | 1 | 91 |
The yearly count peaked at 297 in 2021 and fell to 176 in 2025. By September 14 this year the file held 91 alerts, the fewest by that date of any year since its stated coverage began, against 126 at the same point in 2025 and 211 in 2021. Does a thinner file mean a quieter health department? Not by this record. Alerts under the COVID19 topic fell from 168 in 2021 to 3 in 2025; set them aside, and the rest rose from 129 to 173 — our subtraction, using the file’s own labels.
Measles, in the titles
Fifty-nine titles in the file mention measles, and they bunch in three years: 18 in 2019, 17 in 2024 and 10 in 2025. The 2024 titles include “Measles Outbreak Update – April 5, 2024” and, on May 30, “Measles Update: End of Outbreak Declaration – May 30, 2024.” This year there are two: “Measles Wastewater Detection in Chicago” on February 18 and “Measles Case Confirmed in International Visitor to Chicago June 23, 2026” on June 24. The file’s own Measles topic label first appears on October 13, 2023 and holds 26 alerts; earlier measles alerts sit under other labels, which is why this count reads the titles.
What the priority label measures
The priority column is meant to convey how quickly an alert needs attention, and its note lists four levels: Urgent, High (the default), Medium and Low. In the file, the way the label is used changes over time. Before June 11, 2021, 665 alerts are marked Low and five Urgent, with nothing in between; the first High appears that day, the last Low on August 16, 2024, and all 267 alerts in 2025 and 2026 are High. So the High count tracks when that label came into use and cannot be read as a measure of urgency over time. Seven alerts carry Urgent, none since September 13, 2021.
| Date | Topic label | Title, as filed |
|---|---|---|
| March 18, 2020 | Viral | URGENT Updated COVID-19 Guidance for Hospitals 03/18/2020 |
| March 20, 2020 | Viral | Urgent: CDPH ORDER: DUTIES OF HOSPITALS AND OTHERS and Guidance on PPE |
| March 22, 2020 | Viral | NEW Resource for Discharge of High-Risk COVID-19 PUI or Confirmed Cases-March 22, 2020 |
| March 24, 2020 | Viral | UPDATED: Resource for Discharge of High-Risk COVID-19 PUI or Confirmed Cases-March 22, 2020 |
| March 28, 2020 | COVID19 | UPDATE: Quarantine/Isolation Facility Intake for Probable and Confirmed COVID-19 Cases |
| June 29, 2021 | Notification | URGENT: Medical Device Recall Philips Respironics |
| September 13, 2021 | Hospital Notification | IDPH: Notice of DEVICE RECALL: Philips Trilogy EV300 Ventilators |
Webinars, newsletters and corrections
By this page’s count of words in the titles, 211 alerts name a webinar, conference or newsletter, and 38 announce a correction. 216 titles begin with “IDPH,” the Illinois Department of Public Health’s initials, and 57 with “CDC.” 1,670 alerts carry attachments the file does not include; its column note points to the Health Alert Network site for them. Each alert has one topic label, but the category column can hold several or none: 713 alerts list more than one category, and 663 list none.
What the file confirms, and what it cannot tell you
Confirmed, as published: each alert’s date, title, topic label, categories, priority label and whether it has attachments. The file does not show how many cases, exposures or overdoses lie behind any alert; who received it or what anyone did next; or the alert text, which this page did not read. Its description calls the file a convenience that complements the Health Alert Network site, and asks anyone using alerts where health or life is at risk to contact the HAN team about other ways to receive them.
Where the record lives
The Health Alert Network alerts file sits on the city’s data portal and mirrors the department’s Health Alert Network site. It was last updated September 14, 2026, and every figure here was computed from it as retrieved on September 16, 2026.
The bottom line
Chicago’s health department has published five alerts in 2026 whose titles begin “Increase in Opioid Overdoses in Chicago,” four of them since June 3, against three such alerts in all its earlier years on file. Its overall alert count is the lowest by September 14 of any year since the file’s stated coverage began, and from 2021 to 2025 the drop of 121 alerts is smaller than the 165-alert drop under the COVID19 topic alone. West Nile alerts arrive only from June through October, and because the way the priority label is used changed, its counts cannot compare urgency from one year to another.
Three questions the file can answer
Did the health department publish a measles alert in 2026? Two titles mention measles: a wastewater detection on February 18 and a case confirmed in an international visitor, published June 24. When do West Nile alerts come? All 102 are dated June through October, and August has the most, 27. Has any alert been marked Urgent recently? Not since September 13, 2021.
- Source: the Chicago Department of Public Health’s Health Alert Network alerts file (yfns-6ztj): 1,835 rows, October 11, 2017 through September 14, 2026, retrieved September 16, 2026, with all 1,835 rows analyzed; every alert identifier is unique.
- Columns read: alert identifier, published date, title, topic, category, priority and attachment flag. The alert texts and abstracts were not selected.
- Overdose alerts: every title containing “overdose”, 20 in all. Grouped as an increase with Chicago in the title when it begins “Increase in Opioid Overdose in Chicago” or “Increase in Opioid Overdoses in Chicago” (8); as an increase with no place when it announces an increase in opioid overdoses and names no place (2); all others as other (10).
- Same-date comparison: each year’s alerts dated on or before September 14, the file’s latest date. The file’s metadata gives its time period as March 2, 2020 onward; earlier alerts are shown as the file holds them.
- Title words: the counts of titles containing webinar, conference or newsletter, or correct, corrected or correction, or beginning with IDPH or CDC, are this page’s matches, not labels in the file. Titles are quoted as filed, with repeated spaces collapsed.
- Not here: no medical advice, no count of illness or overdoses, and no cause for any change.
Computed by KCM Desk from the Chicago Department of Public Health’s Health Alert Network alerts file, retrieved September 16, 2026. Human-guided and edited — about this desk. If you spot an error, corrections come first.