Impact assessment of vaccine-related negative news and incentive measures on vaccine hesitancy in Hong Kong

Vaccine hesitancy underscores the critical need to quantify the influence of diverse factors on vaccine uptake. In this study, we develop a social-epidemiological transmission model with an imitation mechanism to characterize the interactions between social and epidemiological dynamics. We introduce a risk score to the payoff function to assess vaccine-related negative news and incentive measures’ impacts on COVID-19 vaccine uptake during the pandemic. By fitting our model with the real data in Hong Kong, we reveal that the vaccine-related negative news drastically impeded vaccination efforts. Scenario analyses suggest that, without incentive measures, the projected fifth wave of COVID-19 in Hong Kong would have infected 98% of the population, resulting in an estimated 51,752 deaths. Both the model simulation and the real data demonstrate that the incentive measures have successfully encouraged vaccine uptake and saved approximately 38,419 lives. However, we found that the willingness to take vaccines quickly declined after the incentive measures were finished, implying limited benefits in mitigating the effect of negative news in the long run. This study also highlights the need for booster doses in the face of the immune escape of the Omicron variants. Our model offers data-driven insights into the interplay between negative news, vaccine hesitancy, and incentive measures, shedding light on the effective preparation for emerging infectious disease outbreaks.