1 Global Research Collaboration for Infectious Disease Preparedness Research and Policy Team, Policy and Practice Research Group, Pandemic Sciences Institute, University of Oxford, Oxford OX3 7BN, UK. Electronic address: alice.norton@ndm.ox.ac.uk.
2 Global Research Collaboration for Infectious Disease Preparedness Research and Policy Team, Policy and Practice Research Group, Pandemic Sciences Institute, University of Oxford, Oxford OX3 7BN, UK.
3 Policy and Practice Research Group, Pandemic Sciences Institute, University of Oxford, Oxford, UK.
4 UK Collaborative on Development Research, London, UK.
5 Cochrane South Africa, South African Medical Research Council, Cape Town, South Africa.