[1] Harvard Medical School and Harvard Pilgrim Health Care,Department of Ambulatory Care and Prevention
[2] Harvard Pilgrim Health Care,Center for Child Health Care Studies
[3] Children's Hospital Boston,Division of General Pediatrics
[4] National Immunization Program,Immunization Safety Branch
[5] Centers for Disease Control and Prevention,Channing Laboratory, Department of Medicine
[6] Brigham and Women's Hospital,undefined
[7] Harvard Medical School,undefined
[8] CDC Eastern Massachusetts Prevention Epicenter,undefined
[9] HMO Research Network Center for Education and Research in Therapeutics,undefined