About the Authors

Calvin K. Y. Cheng

Affiliation School of Public Health, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China

Hing Channarith

Affiliation The Cambodian Children’s Advocacy Foundation, Phnom Penh, Cambodia

Benjamin J. Cowling

bcowling@hku.hk

Affiliation School of Public Health, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China

Competing Interests

BJC has received research funding from MedImmune Inc., and consults for Crucell NV. BJC is an Academic Editor for PLOS ONE. This does not alter the authors’ adherence to all the PLOS ONE policies on sharing data and materials. The authors report no other potential conflicts of interest.

Author Contributions

Conceived and designed the experiments: CKYC. Analyzed the data: CKYC. Wrote the paper: CKYC. Critically revised the manuscript and approved the final version: HC BJC.