About the Authors

Oon Tek Ng

oontek@gmail.com

Affiliation Department of Infectious Disease, Tan Tock Seng Hospital, Singapore

Angela L. Chow

Affiliations Department of Clinical Epidemiology, Tan Tock Seng Hospital, Singapore, Department of Epidemiology and Public Health, National University of Singapore, Singapore

Vernon J. Lee

Affiliations Department of Clinical Epidemiology, Tan Tock Seng Hospital, Singapore, Department of Epidemiology and Public Health, National University of Singapore, Singapore

Mark I. C. Chen

Affiliations Department of Clinical Epidemiology, Tan Tock Seng Hospital, Singapore, Department of Epidemiology and Public Health, National University of Singapore, Singapore

Mar Kyaw Win

Affiliation Department of Clinical Epidemiology, Tan Tock Seng Hospital, Singapore

Hiok Hee Tan

Affiliation Department of Sexually Transmitted Infection Control, National Skin Centre, Singapore

Arlene Chua

Affiliation Department of Infectious Disease, Tan Tock Seng Hospital, Singapore

Yee Sin Leo

Affiliation Department of Infectious Disease, Tan Tock Seng Hospital, Singapore

Competing Interests

The authors have the following interests: V J Lee reported receipt of GlaxoSmithKline funding for unrelated research. There are no patents, products in development or marketed products to declare. This does not alter the authors' adherence to all the PLoS ONE policies on sharing data and materials, as detailed online in the guide for authors.

Author Contributions

Conceived and designed the experiments: OTN ALC VJL MICC YSL. Performed the experiments: MKW HHT AC. Analyzed the data: OTN ALC VJL MICC. Contributed reagents/materials/analysis tools: OTN ALC VJL MICC MKW HHT AC YSL. Wrote the paper: OTN ALC VJL MICC. Critical revision of the manuscript for important intellectual content: OTN ALC VJL MICC MKW HHT AC YSL Statistical analysis: OTN Obtaining funding: OTN VJL Supervision: OTN ALC MKW HHT AC YSL.