Funding for this research was provided by:
Wellcome Trust (101815/Z/13/Z)
Bill and Melinda Gates Foundation (OPP1135522)
Associação Brasileira de Saúde Coletiva
Received: 11 February 2017
Accepted: 24 July 2017
First Online: 18 August 2017
Ethics approval and consent to participate
: Ethical approval was the responsibility of the institution that conducted or commissioned the survey. All datasets used in this paper were de-identified.
: Not applicable.
: The authors declare that they have no competing interests.
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