School of Mathematics and Statistics, Shaanxi Normal University, Xi'an, 710062, People's Republic of China.
Natural Resources Institute, University of Greenwich at Medway, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK.
J Math Biol. 2024 Apr 14;88(6):62. doi: 10.1007/s00285-024-02083-y.
The design of optimized non-pharmaceutical interventions (NPIs) is critical to the effective control of emergent outbreaks of infectious diseases such as SARS, A/H1N1 and COVID-19 and to ensure that numbers of hospitalized cases do not exceed the carrying capacity of medical resources. To address this issue, we formulated a classic SIR model to include a close contact tracing strategy and structured prevention and control interruptions (SPCIs). The impact of the timing of SPCIs on the maximum number of non-isolated infected individuals and on the duration of an infectious disease outside quarantined areas (i.e. implementing a dynamic zero-case policy) were analyzed numerically and theoretically. These analyses revealed that to minimize the maximum number of non-isolated infected individuals, the optimal time to initiate SPCIs is when they can control the peak value of a second rebound of the epidemic to be equal to the first peak value. More individuals may be infected at the peak of the second wave with a stronger intervention during SPCIs. The longer the duration of the intervention and the stronger the contact tracing intensity during SPCIs, the more effective they are in shortening the duration of an infectious disease outside quarantined areas. The dynamic evolution of the number of isolated and non-isolated individuals, including two peaks and long tail patterns, have been confirmed by various real data sets of multiple-wave COVID-19 epidemics in China. Our results provide important theoretical support for the adjustment of NPI strategies in relation to a given carrying capacity of medical resources.
优化非药物干预（NPIs）的设计对于有效控制 SARS、A/H1N1 和 COVID-19 等传染病的突发疫情至关重要，以确保住院病例数量不超过医疗资源的承载能力。为了解决这个问题，我们制定了一个经典的 SIR 模型，其中包括密切接触者追踪策略和结构化预防和控制中断（SPCIs）。我们从数值和理论上分析了 SPCIs 的时机对未隔离感染者数量的最大值和隔离区外传染病持续时间（即实施动态零病例政策）的影响。这些分析表明，为了使未隔离感染者数量的最大值最小化，启动 SPCIs 的最佳时间是当它们可以控制疫情第二次反弹的峰值等于第一次峰值时。在 SPCIs 期间进行更强有力的干预时，第二波疫情的高峰期可能会感染更多的人。SPCIs 期间干预时间越长，接触追踪强度越大，对缩短隔离区外传染病持续时间的效果就越好。通过对中国多波 COVID-19 疫情的多个实际数据集的分析，证实了隔离和未隔离个体数量的动态演变，包括双峰和长尾模式。我们的研究结果为根据给定的医疗资源承载能力调整 NPI 策略提供了重要的理论支持。
