1. Department of Behavioral Sciences and Health Education, Emory University School of Public Health, 1518 Clifton Road NE, Atlanta, GA 30322, USA
2. Klein Buendel, Inc., 1667 Cole Boulevard, Suite 225, Golden, CO 80401, USA
3. Immunization Services Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road NE, Atlanta, GA 30329, USA