The Global Health Monitor update for September reports a sharp rise in the US measles forecast for 2027 and an accelerating chikungunya season in France, while the respiratory outlook holds steady.
Compared with the [August edition](https://www.metaculus.com/notebooks/45388/global-health-monitor-update-august-2026/), predictions this month show:
* Forecasters raised their 2027 US measles estimate 28% to [<u>4,494 cases</u>](https://www.metaculus.com/questions/44970/how-many-measles-cases-will-be-reported-in-the-us-and-the-eea-in-2027/), after a second rise in 2026 pushed [<u>confirmed</u>](https://www.cdc.gov/measles/data-research/index.html) cases to 3,294. Even the low end of the 50% prediction interval would be higher than any year since 1992. The European forecast remained steady, at [<u>3,284 cases</u>](https://www.metaculus.com/questions/44970/how-many-measles-cases-will-be-reported-in-the-us-and-the-eea-in-2027/).
* The Bundibugyo Ebola outbreak in eastern DRC keeps growing, while Uganda [<u>declared</u>](https://www.cdc.gov/ebola/situation-summary/index.html) its own outbreak over on August 25. Forecasters hold the chance of a [<u>first US case </u>](https://www.metaculus.com/questions/45008/will-the-us-confirm-a-bundibugyo-ebola-case-before-july-2027/)before July 2027 at 10%, citing the 21-day travel restriction and the evacuation of exposed workers to Germany rather than the US.
* US screwworm expectations for 2027 edged up by 7% to [<u>49 animal cases</u>](https://www.metaculus.com/questions/44965/how-many-us-new-world-screwworm-animal-cases-will-there-be-in-2027/), as detections within 100 miles of the border in Mexico keep creating chances for spillover.
* The respiratory outlook is steady, with peak [<u>weekly hospital admissions per 100,000</u>](https://www.metaculus.com/questions/44971/what-will-202627-peak-hospitalization-rates-be-for-these-illnesses/) forecast at 10.8 for influenza and a combined peak of 15.5 around January 3. Forecasters expect a milder H3N2 season than the historical pattern, since subclade K dominated last year and the 2026/27 vaccine was updated to match it.
* The locally acquired chikungunya forecast rose 21% to [<u>98 cases in Europe</u>](https://www.metaculus.com/questions/45018/how-many-locally-acquired-chikungunya-cases-in-the-eea-in-2026/) this year, after France went from 15 to [<u>57 local cases</u>](https://www.ecdc.europa.eu/en/chikungunya-virus-disease/surveillance-and-updates/seasonal-surveillance) in a month with most clusters still active.
# [Read the full report](https://www.metaculus.com/files/Global-Health-Monitor-Update-September-2026)
# [Share your forecasts](https://www.metaculus.com/tournament/global-health-monitor-26-27/)
