People are likely to engage in collective behaviour online during extreme
events, such as the COVID-19 crisis, to express their awareness, actions and
concerns. Hong Kong has implemented stringent public health and social measures
(PHSMs) to curb COVID-19 epidemic waves since the first COVID-19 case was
confirmed on 22 January 2020. People are likely to engage in collective
behaviour online during extreme events, such as the COVID-19 crisis, to express
their awareness, actions and concerns. Here, we offer a framework to evaluate
interactions among individuals emotions, perception, and online behaviours in
Hong Kong during the first two waves (February to June 2020) and found a strong
correlation between online behaviours of Google search and the real-time
reproduction numbers. To validate the model output of risk perception, we
conducted 10 rounds of cross-sectional telephone surveys from February 1
through June 20 in 2020 to quantify risk perception levels over time. Compared
with the survey results, the estimates of the risk perception of individuals
using our network-based mechanistic model capture 80% of the trend of people
risk perception (individuals who worried about being infected) during the
studied period. We may need to reinvigorate the public by engaging people as
part of the solution to live their lives with reduced risk