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

Vaccine hesitancy underscores the critical need to quantify how diverse factors shape vaccine uptake. We develop a social-epidemiological transmission model with a game-theoretic imitation mechanism and payoff-driven risk perception to assess the impacts of vaccine-related negative news and incentive measures on COVID-19 vaccine uptake during the pandemic. By fitting our model with real-world data from Hong Kong, we reveal that the negative news drastically impeded vaccination efforts. Scenario analyses suggest that, without incentive measures, the projected fifth wave of COVID-19 in Hong Kong (from December 31, 2021, to October 15, 2022) would have infected 97.3% of the population, resulting in an estimated 48,892 deaths. Both model simulation and real-world data demonstrate that incentive measures have successfully encouraged vaccine uptake and saved approximately 39,073 lives. However, we found that vaccine willingness declined rapidly after the incentive measures discontinued, 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.