2021年初河北省和黑龙江省COVID-19传播差异性的对比

Comparison of the transmission of COVID-19 between Hebei and Heilongjiang in early 2021

目的对2021年1月2日至2021年3月3日河北省和2020年12月10日至2021年2月28日黑龙江省COVID-19传播的差异性进行对比研究,为疫情防控策略的制定提供理论支撑。方法基于2021年初河北省和黑龙江省的现存无症状病例数、现存确诊病例数与累计移出病例数,构建一类阶段性控制策略的动力学模型,利用非线性最小二乘法估计模型参数;利用参数敏感性分析探讨关键参数对两个地区现存确诊病例数峰值及峰值时间的影响。分别分析初期接触数、初期接触传播概率、潜伏者的传染力校正因子与有症状感染者构成比的强弱变化对两个地区的现存无症状病例数、现存确诊病例数与累计移出病例数的影响。结果两个地区的模型拟合效果均良好;与河北省相比,黑龙江省的无症状感染者构成比较大;当初期接触数、初期接触传播概率、潜伏者的传染力校正因子与有症状感染者构成比分别减少10%时,黑龙江省的现存无症状病例数峰值、现存确诊病例数峰值与累计移出病例数的平均减少幅度均较河北省的大。结论2021年初河北省和黑龙江省的COVID-19疫情传播存在明显差异,尤其是控制措施的强弱变化对不同地区疫情发展的影响不同。

Objective To compare the diversity of transmission of COVID-19 in Hebei and Heilongjiang Province in early 2021,and to provide theoretical support for the formulation of prevention and control strategies for COVID-19.Methods A dynamical model with staged control strategies was constructed based on the number of existing asymptomatic cases,the number of existing confirmed cases and the cumulative number of removed cases in Hebei and Heilongjiang at the beginning of 2021.Parameters of the model were estimated by the nonlinear least square method.Sensitivity analysis was used to explore the impact of key parameters on the peak number and peak time of existing confirmed cases in the two regions.We respectively analyzed the influence of the change for the number of initial contacts,the probability of initial contacts,the relative infectivity correction factor of the latent and the composition ratio of the symptomatic infection on the number of existing asymptomatic cases,the number of existing confirmed cases and the number of cumulative cases in the two regions.Results The model fitting results of the two regions were good.Compared the results of Hebei with those of Heilongjiang,there was a larger proportion of asymptomatic infected persons.When the number of initial contacts,the probability of initial contacts,the relative infectivity correction factor of the latent and the composition ratio of the symptomatic infection separately decreased by 10%,the average decrease for the peak number of existing asymptomatic and existing confirmed cases,and the cumulative removed cases in Heilongjiang were more than those in Hebei.Conclusions In early 2021,the transmissions of COVID-19 in Hebei and Heilongjiang were significantly different.In particular,the impact of control measures on the development of the epidemic is different in different areas.