Muscle-wasting diseases, especially those that progress in severity, can damage muscles involved with breathing. Catching the flu is particularly hazardous for those with muscular dystrophies, spinal muscular atrophy and amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease).

In a released statement, Valerie Cwik, MDA's vice president for research and its medical director, said, "Both adults and children with neuromuscular diseases may already have weakened respiratory systems. MDA provides flu shots to reduce their likelihood of developing another, possibly life-threatening, illness."