1. Wellcome Trust Major Overseas Programme; Oxford University Clinical Research Unit; Ho Chi Minh City Vietnam
2. Nuffield Department of Clinical Medicine; Centre for Tropical Medicine and Global Health; Oxford UK
3. UK Division of Virology; Department of Pathology; University of Cambridge; Cambridge UK
4. The Department of Medicine; University of Cambridge; Cambridge UK
5. Center for Infectious Disease Dynamics; Department of Biology; Pennsylvania State University; State College PA USA