We received no funding specifically for this systematic review. ELT is funded in part by awards R01-AI141444 from the National Institute of Allergy and Infectious Diseases and R01-MH120649 from the US National Institute of Mental Health; both Institutes are part of the National Institutes of Health (NIH). JAG and ACP's support of this project was made possible (in part) by grant number UL1TR002553 from the National Center for Advancing Translational Sciences of the NIH, and the NIH Roadmap for Medical Research. JEM is supported by an Australian National Health and Medical Research Council Career Development Fellowship (APP1143429). SN was supported by an award that is jointly funded by the UK Medical Research Council (MRC) and the UK Department for International Development (DFID) under the MRC/DFID Concordat agreement, and part of the EDCTP2 programme supported by the European Union (grant reference MR/R010161/1). ABF acknowledges funding support from the National Health and Medical Research Council of Australia (grant ID 1183303). KH is funded by a National Institute for Health Research Senior Research Fellowship SRF-2017-10-002. The contents of the research included in this manuscript are solely the responsibility of the authors and do not necessarily represent the official views of any of the funders. The research contributed by all authors of this manuscript are independent of their funders. Specifically, the funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We wish to thank the three reviewers for their insightful comments and constructive feedback.