Dr. Eric Ball examines a healthy 5-day-old patient in his office in Ladera Ranch, Calif. Ball and colleagues decided this week to take only patients whose parents follow the recommended vaccine schedule.
Courtesy of Eric Ball
Public school student Julio Valenzuela, 11, grimaces as he gets a vaccination before the start of the school in Lynnwood, Calif., on Aug. 27. Vaccines are required for school attendance.
ROBYN BECK/AFP/Getty Images
Two boys study together at a Chicago yeshiva in 2009. Public health officials say this type of close physical contact caused a mumps outbreak to spread throughout several orthodox Jewish communities in and around New York City.
M. Spencer Green/AP