The ongoing pandemic disease COVID‑19 has caused worldwide social and financial disruption. As many countries are engaged in designing vaccines, the harmful second and third waves of COVID‑19 have already appeared in many countries. To investigate changes in transmission rates and the effect of social distancing in the USA, we formulate a system of ordinary differential equations using data of confirmed cases and deaths in these states: California, Texas, Florida, Georgia, Illinois, Louisiana, Michigan, and Missouri. Our models and their parameter estimations show social distancing can reduce the transmission of COVID‑19 by 60% to 90%. Thus, obeying the movement restriction rules is crucial in reducing the magnitude of the outbreak waves. This study also estimates the percentage of people who were not social distancing ranges between 10% and 18% in these states. Our analysis shows the management restrictions taken by these states do not slow the disease progression enough to contain the outbreak.

持续流行的新型冠状病毒肺炎 (COVID-19) 已造成全球社会和金融混乱。随着许多国家都在忙于设计疫苗，有害的第二波和第三波COVID-19已经在许多国家出现。为了调查美国传播率的变化和社交距离的影响，我们使用以下州的确诊病例和死亡数据制定了一个常微分方程组：加利福尼亚州、德克萨斯州、佛罗里达州、佐治亚州、伊利诺伊州、路易斯安那州、密歇根州和密苏里州。我们的模型及其参数估计显示，社交距离可以将 COVID-19 的传播减少 60% 至 90%。因此，遵守行动限制规则对于减少疫情爆发的规模至关重要。这项研究还估计，在这些州，不保持社交距离的人口比例在 10% 到 18% 之间。我们的分析表明，这些州采取的管理限制并没有减缓疾病的进展，不足以遏制疫情的爆发。