AFM Confirmed U.S. Cases
^ Confirmed AFM cases that CDC has been made aware of as of December 7, 2018 with onset of the condition through November 30, 2018. The 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 limb weakness and an MRI showing spinal cord lesion largely restricted to gray matter and spanning one or more spinal segments, regardless of age.
For more information, visit the Case Definitions page.
The graph shows the number of AFM cases confirmed by CDC as of December 7, 2018, with onset of the condition through November 30, 2018.
- So far in 2018, there are 158 confirmed cases of AFM. (Note: The cases occurred in 36 states across the U.S.)
Note: These 158 confirmed cases are among the total of 311 reports that CDC received of patients under investigation (PUIs). CDC recently received increased reports for PUIs with onset of symptoms in August, September, and October. CDC and state and local health departments are still investigating some of these PUIs. With enhanced efforts working with local and state health departments and hospitals, we were able to gather information on PUIs and confirm a number of these cases faster. CDC is now providing the number of patients still under investigation so people can better anticipate increases in confirmed cases over the coming months.
- In 2017, CDC received information for 35 confirmed cases of AFM. (Note: The cases occurred in 16 states across the U.S.)
- In 2016, 149 people were confirmed to have AFM. (Note: The cases occurred in 39 states across the U.S. and DC)
- In 2015, 22 people were confirmed to have AFM. (Note: The cases occurred in 17 states across the U.S.)
- From August to December 2014, 120 people were confirmed to have AFM. (Note: The cases occurred in 34 states across the U.S.)
- The case counts represent only those cases for which information has been sent to and confirmed by CDC.
It is currently difficult to interpret trends of the AFM data. Collecting information about patients under investigation (PUIs) for AFM is relatively new. There may initially be more variability in the AFM data from year to year making it difficult to interpret or compare case counts between years.
We defer to the states to release additional information on cases as they choose.
- Page last reviewed: December 10, 2018
- Page last updated: December 10, 2018
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