Abraham Baldwin Agricultural College, Tifton, GA, USA.
Morgan State University, Baltimore, MD, USA.
Math Med Biol. 2023 Dec 15;40(4):308-326. doi: 10.1093/imammb/dqad007.
The emergence of multiple strains of SARS-COV-2 has made it complicated to predict and control the COVID-19 pandemic. Although some vaccines have been effective in reducing the severity of the disease, these vaccines are designed for a specific strain of the virus and are usually less effective for other strains. In addition, the waning of vaccine-induced immunity, reinfection of recovered people, and incomplete vaccination are challenging to the vaccination program. In this study, we developed a detailed model to describe the multi-strain transmission dynamics of COVID-19 under vaccination. We implemented our model to examine the impact of inter-strain transmission competition under vaccination on the critical outbreak indicators: hospitalized cases, undiagnosed cases, basic reproduction numbers, and the overtake-time by a new strain to the existing strain. In particular, our results on the dependence of the overtake-time on vaccination rates, progression-to-infectious rate, and relative transmission rates provide helpful information for managing a pandemic with circulating two strains. Furthermore, our results suggest that a reduction in the relative transmission rates and a decrease in vaccination dropout rates or an increase in vaccination rates help keep the reproduction number of both strains below unity and keep the number of hospitalized cases and undiagnosed cases at their lowest levels. Moreover, our analysis shows that the second and booster-dose vaccinations are useful for further reducing the reproduction number.
多种 SARS-CoV-2 株系的出现使得预测和控制 COVID-19 大流行变得复杂。尽管一些疫苗在降低疾病严重程度方面有效，但这些疫苗是针对病毒的特定株系设计的，对其他株系通常效果较差。此外，疫苗诱导的免疫力减弱、已康复人群的再次感染以及不完全接种疫苗对疫苗接种计划构成挑战。在这项研究中，我们开发了一个详细的模型来描述 COVID-19 在接种疫苗下的多株系传播动力学。我们实施了我们的模型来研究接种疫苗下的株间传播竞争对关键爆发指标的影响：住院病例、未确诊病例、基本繁殖数以及新株超过现有株的时间。特别是，我们关于超越时间对疫苗接种率、进展为传染性率和相对传播率的依赖关系的结果为管理两种流行株循环的大流行提供了有用的信息。此外，我们的结果表明，降低相对传播率以及降低疫苗接种脱落率或提高疫苗接种率有助于将两种株系的繁殖数保持在 1 以下，并将住院病例和未确诊病例数量保持在最低水平。此外，我们的分析表明，第二剂和加强剂疫苗接种对于进一步降低繁殖数是有用的。
