(Undated) -- America is observing Prematurity Awareness Month right now. Pediatrician Dr. Jonathan Popler says there's a pretty-clear definition of prematurity. Dr. Popler says prematurity is common in the U.S., making up eleven-percent of the birthrate. That's about half-a-million babies-per-year. Dr. Poplar says a big worry in premature babies is infection, particularly with the dangerous RSV respiratory virus. Dr. Poplar says the drugmaker AstraZeneca is now offering a new RSV medication called Synagis.