1. Centers for Disease Control and Prevention, Atlanta, Georgia, USA;New York City Department of Health and Mental Hygiene, New York, New York, USA;
2. Centers for Disease Control and Prevention, Atlanta, Georgia, USA;
3. Johns Hopkins University, Baltimore, Maryland, USA;
4. Emory University School of Medicine and the VA Medical Center, Atlanta, Georgia, USA;
5. Mount Sinai Hospital, Toronto, Ontario, Canada