title: Expanding and contracting.
authors.affiliation: Editor, The Lancet Global Health.
authors.forename: Zoë
authors.initials: Z
authors.lastname: Mullan
mesh_terms: D000755:Anemia, Sickle Cell; D054242:Emigrants and Immigrants; D014943:Global Health; D006801:Humans; D015994:Incidence; D008288:Malaria / Q000517:prevention & control; D011051:Poliomyelitis / Q000517:prevention & control; D014611:Vaccination