Among many ongoing investigation activities to determine the cause of AFM, CDC is looking at any possible association between intramuscular injections given in healthcare settings, such as medications and vaccines, and AFM. CDC collects medical information on all suspected cases of AFM in the United States that are reported to us from health departments. A history of intramuscular injections received in the 30 days prior to limb weakness is recorded for all cases. Of the AFM cases reviewed thus far, approximately 85% have no recorded vaccination in the 30 days prior to the onset of limb weakness.