Affiliations

• ¹ National Centre for Immunisation Research and Surveillance of Vaccine-Preventable Diseases, Kids Research Institute, Sydney Children's Hospitals Network and University of Sydney, Sydney, NSW 2145, Australia. Electronic address: peter.mcintyre@health.nsw.gov.au.
• ² National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.