The recent experience of SARS-CoV-2 epidemics spreading revealed the importance of passive forms of infection transmissions. Apart from the virus survival outside the host, the latent infection transmissions caused by asymptomatic and presymptomatic hosts represent major challenges for controlling the epidemics. In this regard, social mixing and various biological factors play their subtle, but often critical, role. For example, a life-threatening condition may result in the infection contracted from an asymptomatic virus carrier. Here, we use a new recently developed microscopic agent-based modelling framework to shed light on the role of asymptomatic hosts and unravel the interplay between the biological and social factors of these nonlinear stochastic processes at high temporal resolution. The model accounts for each human actor’s susceptibility and the virus survival time, as well as traceability along the infection path. These properties enable an efficient dissection of the infection events caused by asymptomatic carriers from those which involve symptomatic hosts before they develop symptoms and become removed to a controlled environment. Consequently, we assess how their relative proportions in the overall infection curve vary with changing model parameters. Our results reveal that these proportions largely depend on biological factors in the process, specifically, the virus transmissibility and the critical threshold for developing symptoms, which can be affected by the virus pathogenicity. Meanwhile, social participation activity is crucial for the overall infection level, further modulated by the virus transmissibility.

最近 SARS-CoV-2 流行病传播的经验揭示了被动形式的感染传播的重要性。除了病毒在宿主外存活，无症状和症状前宿主引起的潜伏感染传播是控制流行病的主要挑战。在这方面，社会混合和各种生物因素发挥着微妙但往往至关重要的作用。例如，危及生命的情况可能导致感染无症状病毒携带者。在这里，我们使用最近开发的基于微观代理的新建模框架来阐明无症状宿主的作用，并以高时间分辨率揭示这些非线性随机过程的生物和社会因素之间的相互作用。该模型考虑了每个人类参与者的易感性和病毒存活时间，以及沿感染路径的可追溯性。这些特性能够有效地将无症状携带者引起的感染事件与涉及有症状宿主的感染事件分开，然后再出现症状并转移到受控环境中。因此，我们评估了它们在整体感染曲线中的相对比例如何随着模型参数的变化而变化。我们的研究结果表明，这些比例在很大程度上取决于该过程中的生物因素，特别是病毒的传播能力和出现症状的临界阈值，这可能会受到病毒致病性的影响。同时，社会参与活动对整体感染水平至关重要，进一步受到病毒传播性的调节。