What to know
As of August 6, 2026, there have been 9 confirmed cases out of 20 patients under investigation (PUIs) in 2026 and 17 confirmed cases out of 36 PUIs in 2025. There have been 799 confirmed cases since CDC began tracking AFM in August of 2014.
Annual AFM cases by state
Annual maps represent only cases for whom information was sent to and confirmed by CDC as of August 6, 2026. Patients under investigation are still being classified, and the case counts are subject to change. Cases of AFM have occurred in 49 states and the District of Columbia since AFM surveillance began.
We defer to the states to release additional information on cases as they choose.
AFM confirmed cases in 2026
As of August 6, 2026, there have been 9 confirmed cases in 7 states.
AFM confirmed cases in 2025
As of August 6, 2026, there have been 17 confirmed cases in 10 states.
Cases by month, 2014-2026
Most patients developed AFM between August and November, with increases in AFM cases in 2014, 2016, and 2018. Many viruses commonly circulate at this same time of year, including enteroviruses, which are likely responsible for the increase in cases in peak years.
Cases by month data table
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sept | Oct | Nov | Dec | Total | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2014 | -- | -- | -- | -- | -- | -- | -- | 21 | 51 | 24 | 15 | 9 | 120 |
| 2015 | 2 | 2 | 1 | 0 | 1 | 0 | 2 | 3 | 1 | 4 | 2 | 4 | 22 |
| 2016 | 1 | 0 | 6 | 1 | 7 | 9 | 13 | 33 | 43 | 27 | 9 | 4 | 153 |
| 2017 | 2 | 5 | 5 | 4 | 2 | 4 | 3 | 1 | 4 | 0 | 3 | 5 | 38 |
| 2018 | 0 | 4 | 1 | 2 | 3 | 8 | 8 | 30 | 88 | 66 | 21 | 7 | 238 |
| 2019 | 2 | 4 | 4 | 3 | 5 | 2 | 5 | 4 | 6 | 7 | 2 | 3 | 47 |
| 2020 | 7 | 3 | 5 | 2 | 1 | 2 | 3 | 3 | 3 | 3 | 1 | 1 | 34 |
| 2021 | 3 | 2 | 3 | 1 | 3 | 3 | 2 | 2 | 2 | 1 | 4 | 3 | 29 |
| 2022 | 2 | 1 | 4 | 2 | 3 | 2 | 2 | 9 | 9 | 5 | 7 | 2 | 48 |
| 2023 | 2 | 3 | 2 | 0 | 1 | 3 | 3 | 1 | 1 | 2 | 0 | 1 | 19 |
| 2024 | 2 | 4 | 1 | 1 | 5 | 0 | 2 | 0 | 4 | 2 | 3 | 1 | 25 |
| 2025 | 0 | 1 | 1 | 4 | 0 | 1 | 1 | 1 | 2 | 1 | 3 | 2 | 17 |
| 2026 | 2 | 0 | 1 | 2 | 3 | 0 | 1 | 9 |
Confirmed cases of AFM by month of illness onset. Case counts are subject to change.
Footnotes:
- Confirmed AFM cases by CDC from August 2014 through August 6, 2026. Case counts are subject to change.
- The data shown from August 2014 to July 2015 are based on the AFM investigation case definition: onset of acute limb weakness on or after August 1, 2014, and a magnetic resonance image (MRI) showing a spinal cord lesion largely restricted to gray matter in a patient age ≤21 years.
- The data shown from August 2015 to present are based on the AFM case definition adopted by the Council of State and Territorial Epidemiologists (CSTE): acute onset of focal or flaccid limb weakness and an MRI showing spinal cord lesion largely restricted to gray matter and spanning one or more spinal segments, regardless of age.
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