1. School of Mathematics and Statistics, The University of Melbourne, Melbourne, Australia
2. Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
3. Department of Paediatrics, Faculty of Medicine, Universitas Sumatera Utara, Medan, Indonesia
4. Eijkman Institute for Infection and Molecular Biology, Jakarta, Indonesia
5. Menzies School of Health Research and Charles Darwin University, Darwin, Australia
6. University of Melbourne, at the Doherty Institute for Infection and Immunity, Melbourne, Australia