title: Editorial response: moving from core groups to risk spaces.
authors: Caroline M
authors: CM
authors: Fichtenberg
authors: Jonathan M
authors: JM
authors: Ellen
mesh_terms: D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D016021:Epidemiologic Studies; D005260:Female; D006801:Humans; D008297:Male; D012725:Sexual Behavior; D012749:Sexually Transmitted Diseases / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control*