University of Miami pediatrician Judith L. Schaechter gives an HPV vaccination to a 13-year-old girl last week in Miami. Joe Raedle/Getty Images hide caption

itoggle caption Joe Raedle/Getty Images

A nurse vaccinates a child against pneumonia at a healthcare center in Managua in January. Nicaragua received pneumococcal vaccines from the GAVI Alliance. ELMER MARTINEZ/AFP/Getty Images hide caption

itoggle caption ELMER MARTINEZ/AFP/Getty Images

Construction at the new Nemours Children's Hospital, at the medical city at Lake Nona, Fla., in late 2010. Joe Burbank/Orlando Sentinel hide caption

itoggle caption Joe Burbank/Orlando Sentinel

Trevor Reese, 13, gets his diphtheria, tetanus and pertussis booster shot from pediatric nurse practitioner Jenny Lu in Tustin, Calif., in August. Jae C. Hong/AP hide caption

itoggle caption Jae C. Hong/AP