Modeling the influence of vaccine passport on the outbreak of epidemic with asymptomatic infection.

Vaccine passport is recognized as a necessary policy to revive the economy during the outbreak of epidemic with asymptomatic infection, and has been widely adopted in the global world. But implementing vaccine passport inevitably increases the infection risk when the vaccine efficacy is not perfect. Choosing a suitable level of vaccine passport with the consideration of vaccine imperfection is extremely important, which is less studied in the existing literature. In this paper, a novel epidemic model is proposed to consider the mixed impacts of vaccination, including vaccination coverage, vaccine efficacy, and vaccine passport, and the heterogeneous mean-filed (HMF) method is used to analyze the model. Both analytical and numerical results indicate that the introduction of vaccine passport will largely weaken the effect of vaccination and decrease the epidemic threshold in either homogeneous or heterogeneous network structure. Especially, when the efficacy of vaccine is lower than a certain value, if vaccine passport is implemented, increasing vaccination coverage may instead increase the number of infections. The results suggest that the proper vaccination-related combinations are: medium/high vaccination coverage, high vaccine efficacy, and low/medium vaccine passport. In addition, the upper bounds of vaccine passport under different combinations of vaccination coverage and vaccine efficacy are explored based on the epidemic threshold. [ABSTRACT FROM AUTHOR]