As of March 2, 2023, there have been 42 confirmed cases in 2022 out of 82 reports of patients under investigation (PUIs) and 1 confirmed case in 2023 out of 7 reports of PUIs (see map AFM Cases and Outbreaks | CDC). In 2021, there were 28 confirmed cases out of 59 reports of PUIs. In 2020, there were 32 confirmed cases out of 59 reports of PUIs. There have been 723 confirmed cases since CDC began tracking AFM in August of 2014. CDC has been thoroughly investigating cases since that time. We have seen increases in AFM cases, mostly in young children, in 2014 (120 cases), 2016 (153 cases) and 2018 (238 cases). CDC recently announced that in August 2022 there was an increase of enterovirus (and specifically of EVD68) detected in children reported in some regions in the U.S. (Health Alert Network No. 474). Pediatricians were encouraged to be alert for cases of Acute Flaccid Myelitis, however despite the respiratory outbreak of EV-D68 in 2022, no significant increase in AFM cases was observed.
Acute flaccid myelitis (AFM) is a rare, polio-like illness. It primarily affects young children, but there have been cases among adolescents and adults. AFM cases in the U.S. have peaked between August and October, with increases in cases seen biennially in 2014–2018. Early detection and medical support are critical to improve long-term health outcomes of children with AFM. Delays in recognition can put children at risk. Pediatricians and pediatric health care providers who can identify AFM and promptly hospitalize patients are well positioned to provide optimal medical care.
- Presentation: The most common symptoms of AFM are sudden onset of arm or leg weakness, loss of muscle tone, and loss of reflexes. Suspect AFM in any child presenting with acute onset weakness, particularly when following a febrile illness in the summer-fall. Detect AFM through a detailed neurologic exam for hypotonic, hyporeflexic limb weakness.
- Diagnosis: Diagnose AFM by obtaining MRI of the brain and spinal cord, and lumbar puncture. Collect respiratory swabs, stool, CSF, and blood as early as possible to look for a cause.
- Complications: AFM can lead to long term complications, including paralysis, and in rare cases, death.
- Precautions: Contact precautions are indicated for infants and young children for the duration of enterovirus illness. Droplet precautions also are indicated for EV-D68 respiratory infections.
- Risk mitigation: Prevent infection by promoting vaccination (ie Inactivacted poliovirus vaccine) and infection control practices (eg hand hygiene, especially after diaper changes, and disinfecting surfaces).
- Management: Manage AFM by hospitalizing any suspected cases in the acute phase and providing respiratory support when needed. Get help from AFM experts by consulting a pediatric neurologist, infectious disease specialist or through the AFM physician support portal.
- Treatment: There is no specific treatment for AFM, recommendations for interventions are made on a case-by-case basis related to the needs of the child and consultation with specialists. For more information see CDC clinical guidance.
- Reporting and assistance: Report any suspected cases of AFM to your state health department and provide requested biological specimens and data.
- Red Book chapters: Enterovirus (Nonpoliovirus) (Group A and B Coxsackieviruses, Echoviruses, Numbered Enteroviruses) | West Nile Virus | Poliovirus Infections
- CDC Acute Flaccid Myelitis (AFM) | CDC
- AAP and CDC Educational Course on Acute Flaccid Myelitis: Acute Flaccid Myelitis - What Pediatricians Should Know About Diagnosis, Treatment, and Care of Pediatric Patients - AAP
Pediatric Practice Tools and Information
Recognize AFM: AFM Clinical Presentation for Clinicians ׀ CDC
Initial Evaluation for AFM ׀ CDCAFM Clinical Guidance | CDC
Public Health Resources
Report cases: AFM Case Definitions | CDC
Collect data: Data Collection for AFM | CDC
Information for Patients and Caregivers
AAP HealthyChildren.org: AFM: What We Know About This Paralyzing Illness
CDC information: For Parents of Children who have AFM | CDC
Infection Prevention and Control Resources