Signs: CDC Urges Clinicians to Promptly Recognize and Rapidly Report Acute
Flaccid Myelitis (AFM) Cases
Release / July 9, 2019 / Vol. 68 Vital Signs: Surveillance for Acute
Flaccid Myelitis每每United States, 2018
Background: Acute flaccid
myelitis (AFM), a serious paralytic illness, was first recognized as a
distinct condition in 2014, when cases were reported concurrent with a
large U.S. outbreak of severe respiratory illness caused by enterovirus
D-68 (EV-D68). Since 2014, nationwide outbreaks of AFM have occurred every
two years in the United States; the cause for the recent change in the
epidemiology of AFM in the United States, including the occurrence of
outbreaks and a biennial periodicity since 2014, is under investigation.
This report updates clinical, laboratory, and outcome data for cases
reported to CDC during 2018.
Methods: Clinical data and
specimens from persons in the United States who met the clinical criterion
for AFM (acute onset of flaccid limb weakness) with onset in 2018 were
submitted to CDC for classification of the illnesses as confirmed,
probable, or non-AFM cases. Enterovirus/rhinovirus (EV/RV) testing was
performed on available specimens from persons meeting the clinical
criterion. Descriptive analyses, laboratory results, and indicators of
early recognition and reporting are summarized.
Results: From January through December 2018, among 374 reported
cases of AFM, 233 (62%) (from 41 states) were classified as confirmed, 26
(7%) as probable, and 115 (31%) as non-AFM cases. Median ages of patients
with confirmed, probable, and non-AFM cases were 5.3, 2.9, and 8.8 years,
respectively. Laboratory testing identified multiple EV/RV types, primarily
in respiratory and stool specimens, in 44% of confirmed cases. Among
confirmed cases, the interval from onset of limb weakness until specimen
collection ranged from 2 to 7 days, depending on specimen type. Interval
from onset of limb weakness until reporting to CDC during 2018 ranged from
18 to 36 days, with confirmed and probable cases reported earlier than
Conclusion: Identification of
risk factors leading to outbreaks of AFM remains a public health priority.
Prompt recognition of signs and symptoms, early specimen collection, and
complete and rapid reporting will expedite public health investigations and
research studies to elucidate the recent epidemiology of AFM and
subsequently inform treatment and prevention recommendations.
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current issue of CDC
Science Clips: Volume 11, Issue 36, September 10, 2019 contains
other articles on AFM which may be of particular interest to clinicians and
public health professionals.