title: Reply to Davey et al.
authors.affiliation: South African Centre for Epidemiological Modelling and Analysis, University of Stellenbosch.
authors.forename: Amitabh B
authors.initials: AB
authors.lastname: Suthar
authors.affiliation: Wits Reproductive Health Institute, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: Brian G
authors.initials: BG
authors.lastname: Williams