aVancouver Infectious Diseases Center, Vancouver bSimon Fraser University, Department of Health Sciences, Burnaby, British Columbia, Canada cCenter of Excellence in Preventive and Integrative Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand dDepartment of Infection Biology & Microbiomes, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK eDepartment of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA fBumrungrad International Hospital, Bangkok, Thailand. Correspondence to Dr Brian Conway, Vancouver Infectious Diseases Centre, British Columbia, 201-1200 Burrard Street, Vancouver, Canada V6Z 2C7. E-mail: [email protected]