Catheryn Salibay, MPH¹, Melissa Dahlke, MPH¹, Jacqueline Chan, BS², Jonathan Strober, MD³, Vi Nguyen, MPH⁴, Eva Weinstein, MPH⁵, Alvin Nelson El Amin, MD⁶, Sandra Jo Hammer, MSN, MPH¹, Gwendolyn Hammer, PhD, MSN, APRN², Robert Schechter, MD⁷, John Talarico, DO, MPH⁷, Kathleen Harriman, PhD, MPH, RN⁷, Carol Glaser, DVM, MD² and Kathleen Winter, MPH¹, 1Immunization Branch, California Department of Public Health, Richmond, CA, 2Communicable Disease Emergency Response Branch, California Department of Public Health, Richmond, CA, 3Neurology and Pediatrics, UCSF, School of Medicine, San Francisco, CA, 4IMMUNIZATION PROGRAM, LOS ANGELES COUNTY DEPARTMENT OF PUBLIC HEALTH, Los Angeles, CA, 5Immunization Program, Los Angeles County Department of Public Health, Los Angeles, CA, 6Immunization Program, LA County Department of Public Health, Los Angeles, CA, 7Immunization Branch, CDPH, Richmond, CA