title: Literature Review.
authors.affiliation: Division of Infectious Diseases, Boston Children's Hospital, Massachusetts.
authors.forename: Ilan
authors.initials: I
authors.lastname: Youngster
authors.affiliation: Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor.
authors.forename: Janet R
authors.initials: JR
authors.lastname: Gilsdorf