1 Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
2 Division of Respiratory and Critical Care Medicine, Department of Medicine, National University of Singapore, Singapore.
3 Emergency Medicine Department, National University of Singapore, Singapore.
4 Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
5 Singapore Immunology Network (SIgN), Immunos Building at Biopolis, Agency for Science, Technology and Research (A∗STAR), Singapore.
6 Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore. Electronic address: pcmngtp@nus.edu.sg.