WATCH: Rate of unvaccinated toddlers increasing

  • Now Playing: New York child dies of pediatric flu


  • Now Playing: New York City reports its first pediatric flu death of the season


  • Now Playing: Trump introduces new plan to reduce Medicare drug prices


  • Now Playing: ‘GMA’ Hot List: What to know about the new FDA-approved flu pill


  • Now Playing: How to do the ultimate festive fall workout


  • Now Playing: FDA approves new, fast-acting flu pill


  • Now Playing: Rate of unvaccinated toddlers increasing


  • Now Playing: FDA approves new flu medication in the form of a single-dose pill


  • Now Playing: 7th child dies from outbreak at NJ rehabilitation center


  • Now Playing: Woman reveals she is a perfect match, will donate kidney to her neighbor


  • Now Playing: What is multiple sclerosis?


  • Now Playing: Aerobic exercise can help relieve symptoms of depression


  • Now Playing: New AFM cases surface in MD and PA


  • Now Playing: Why black women have worse breast cancer outcomes


  • Now Playing: Expert tips on how to keep your skin hydrated this winter


  • Now Playing: How ‘strong’ has become the ‘new healthy’


  • Now Playing: Salmonella outbreak resistant to some drugs linked to raw chicken


  • Now Playing: Neck collars providing answers to subconcussive impacts


  • Now Playing: Is this the ultimate cure for hiccups? Dr. Ian Smith breaks down old-school remedies


  • Now Playing: Male breast cancer survivor shares his journey