Despite surges in enterovirus D68 infections in 2022, 2024, and 2025, confirmed cases of acute flaccid myelitis (AFM) — a rare, polio-like neurologic condition — did not rise in tandem, new CDC data show. Researchers suggest newer EV-D68 strains may be less capable of attacking the nervous system. Still, clinicians are urged to stay alert and report suspected AFM cases promptly.
Spikes in enterovirus D68 (EV-D68) infections over the past several years haven't translated into a corresponding rise in acute flaccid myelitis (AFM), a rare, polio-like condition that causes sudden limb weakness, according to a new CDC report in the Morbidity and Mortality Weekly Report. This breaks from the pattern seen in 2018, when EV-D68 and AFM cases rose together.
Researchers hypothesize that newer circulating EV-D68 strains may simply be less neurovirulent — mouse studies have shown recent dominant strains lack key proteins linked to nerve damage. Still, the CDC is urging clinicians not to let their guard down, especially given the unexpected EV-D68 surge in 2025.
By the Numbers:
Why it matters: AFM is clinically indistinguishable from polio, making vigilant surveillance and stool specimen collection critical — not just for managing AFM, but for confirming the continued elimination of polio in the U.S.
