Exposure setting has played a critical role in the pattern of virus transmission in the Coronavirus Diseases 2019 (COVID-19) pandemic. This study investigates the population risks of exposure to SARS-CoV-2 and other respiratory pathogens in different exposure settings in Hong Kong. The study results would be important for informing public health policy development to achieve effective control of epidemics.

This is an anonymous survey. Participation is limited to ONE person from each household, who is aged 18 or above and is normally living in Hong Kong. Consented participants will be invited to answer a baseline survey at study enrolment which can be completed in 10-15 minutes. In the baseline questionnaire, the following will be enquired: (A) socio-demographics, (B) history of SARS-CoV-2 infection, exposure, and testing, (C) activities in the past 1 month related to SARS-CoV-2 exposure in different settings (household, workplace/school, daily activity, social and healthcare setting) and (D) history of COVID-19 vaccination. In the ensuing 36 months after the completion of the baseline questionnaire, participants will be invited to complete monthly updates, which are simpler questionnaires which can be completed in about 5 minutes. Participants will be asked to update information in section (B) and (C) based on their activities in the past 1 month. Monthly reminder will be sent through email. Depending on the changes in epidemic level and social distancing regulation, additional updates might be requested at selected time-points.

A participant who has completed the baseline questionnaire is entitled to receive a supermarket voucher worth HKD50. Additional supermarket vouchers (each HKD50) would be offered to participants who complete at least 3 monthly updates in every 6 months (months 1-6, months 7-12, months 13-18 and so on). Participants of this study may also be invited to join a follow-up household study involving COVID-19 antibody testing, which is free-of-charge. Details of this study will be announced after the completion of baseline questionnaire.

Participation in this study will not subject the respondents to any foreseeable psychological, physiological, social, legal or commercial risks or benefits. Participation in this study is completely voluntary. You may quit this study whenever you wish. All data collected in this study will be kept strictly confidential and reported only in aggregate form for publicity and publication in academic journals.

Should you have any enquiries about this study, please contact us at 2252-8862 at office hours or via ceidstudy@cuhk.edu.hk.