title: THE AUTHORS REPLY.
authors.affiliation: Department of Obstetrics and Gynaecology, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Hutcheon
authors.affiliation: Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, QC, Canada.
authors.forename: Deshayne B
authors.initials: DB
authors.lastname: Fell
authors.affiliation: Group Health Research Institute, Seattle, WA.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Jackson
authors.affiliation: Department of Pediatrics, McGill University, Montreal, QC, Canada.|Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, QC, Canada.|Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, QC, Canada.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Kramer
authors.affiliation: Initiative for Vaccine Research, World Health Organization, Geneva, Switzerland.|Departments of Epidemiology and Obstetrics and Gynecology, Brown University, Providence, RI.
authors.forename: Justin R
authors.initials: JR
authors.lastname: Ortiz
authors.affiliation: Initiative for Vaccine Research, World Health Organization, Geneva, Switzerland.
authors.forename: David A
authors.initials: DA
authors.lastname: Savitz
authors.affiliation: Department of Pediatrics, McGill University, Montreal, QC, Canada.|Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, QC, Canada.|Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, QC, Canada.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Platt