Recently, four new strains of SARS-COV-2 were reported in different countries which are mutants and considered as 70$\%$ more dangerous than the existing covid-19 virus. In this paper, hybrid mathematical models of new strains and co-infection in Caputo, Caputo-Fabrizio, and Atangana-Baleanu are presented. The idea behind this co-infection modeling is that, as per medical reports, both dengue and covid-19 have similar symptoms at the early stages. Our aim is to evaluate and predict the transmission dynamics of both deadly viruses. The qualitative study via stability analysis is discussed at equilibria and reproduction number ${\mathcal{R}}_0$ is computed. For the numerical purpose, Adams-Bashforth-Moulton and Newton methods are employed to obtain the approximate solutions of the proposed model. Sensitivity analysis is carried out to assessed the effects of various biological parameters and rates of transmission on the dynamics of both viruses. We also compared our results with some reported data against infected, recovered, and death cases.

最近，不同国家报告了四种新的 SARS-COV-2 毒株，它们是突变体，被认为是 70$\%$比现有的 covid-19 病毒更危险。在本文中，介绍了卡普托、卡普托-法布里奇奥和阿坦加纳-巴莱努的新菌株和共感染的混合数学模型。这种合并感染模型背后的想法是，根据医学报告，登革热和 covid-19 在早期阶段都有相似的症状。我们的目标是评估和预测这两种致命病毒的传播动态。通过稳定性分析的定性研究在平衡和再生数方面进行了讨论${\mathcal{R}}_0$被计算。出于数值目的，采用 Adams-Bashforth-Moulton 和 Newton 方法来获得所提出模型的近似解。进行敏感性分析以评估各种生物学参数和传播速率对两种病毒动力学的影响。我们还将我们的结果与一些报告的感染、康复和死亡病例数据进行了比较。