The National Institutes of Health (NIH) is sponsoring a clinical trial to evaluate the safety of an investigational monoclonal antibody to treat enterovirus D68 (EV-D68), which can cause severe respiratory and neurological diseases such as acute flaccid myelitis (AFM) – similar to polio. Scientists are striving to better understand AFM, which has emerged in the United States with spikes in cases every other year, primarily in the late-summer months over the last decade.