Funding for this research was provided by:
Bill and Melinda Gates Foundation
University of Oxford Clarendon Fund
Received: 8 January 2020
Accepted: 14 April 2020
First Online: 2 June 2020
Ethics approval and consent to participate
: Ethics approval for the IPD meta-analysis of anonymized secondary data was waived by the Oxford Tropical Research Ethics Committee. Obtaining consent to participate is not required as this study consists of anonymized secondary data.
: Not applicable.
: The authors declare that they have no competing interests.