1. Immunization Safety Office, Division of Healthcare Quality Promotion and
2. Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland; and
3. Epidemiology Intelligence Service, Meningitis and Vaccine Preventable Diseases Branch, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia;
4. Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan