Vaccine Allocation Strategy for Addressing Vaccine-Induced Asymptomatic Infections

This study investigates the role of mass vaccination in mitigating the impact of infectious diseases, with a focus on the often-overlooked issue of asymptomatic carriers among vaccinated individuals. To accurately capture the occurrence of asymptomatic infections after vaccination, we propose a SEIAQ model that incorporates age-specific contact patterns in a population. Using census data from Shanghai, China, we simulate the potential transmission of the disease in an age-specific structured population. In light of potential constraints on vaccine coverage during the early stages of an epidemic, we also propose a vaccine allocation strategy that prioritizes different age groups based on the next-generation matrix concept. Our simulation results demonstrate that this strategy significantly reduces overall infections and the proportion of symptomatic infections. These findings highlight the effectiveness of the proposed strategy in containing disease spread, particularly when the vaccine may not fully prevent asymptomatic infections.