title: Reply to Chen et al.
authors: Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut.
authors: Ted
authors: T
authors: Cohen
authors: Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut.
authors: Leonid
authors: L
authors: Chindelevitch
authors: Infection Prevention and Control.
authors: Reshma
authors: R
authors: Misra
authors: Brigham and Women's Hospital.
authors: Maria E
authors: ME
authors: Kempner
authors: Partners in Health, Boston, Massachusetts.
authors: Jerome
authors: J
authors: Galea
authors: Infection Prevention and Control.
authors: Prashini
authors: P
authors: Moodley
authors: Department of Internal Medicine, Edendale Hospital, Pietermaritzburg, University of KwaZulu-Natal, South Africa.
authors: Douglas
authors: D
authors: Wilson