目的：研究截止2021年11月25日新型冠状病毒变异毒株奥密克戎（Omicron）的早期流行发展情况，在此基础上，估计本次奥密克戎变异株造成的疫情的基本再生数（R_0）以及潜伏期和世代间隔等几个较为重要的流行病学参数。
方法：使用威布尔分布、伽马分布、对数正态分布分别拟合从通报的病例信息中得到的潜伏期及世代间隔的数据信息的概率分布。考虑疫情流行的一般性规律，使用指数增长模型拟合2021年11月16日至2021年11月25日的疫情数据，并利用指数增长法和SEIR模型分别估计基本再生数（R_0）的值。
结果：截止2021年11月25日，早期疫情数据基本符合指数增长，其中截止2021年11月23日的指数拟合程度较好。使用威布尔分布、伽马分布、对数正态分布分别拟合数据所得的平均潜伏期分别为：3.88、3.87、3.88天，平均世代间隔分别为：5.78、5.81、5.82天。使用指数增长法和SEIR模型分别估计R_0的值为：5.96、5.95。
结论：新型冠状病毒变异毒株奥密克戎（Omicron）所导致的疫情与初始毒株所致疫情相比，有以下特点：1、更短的潜伏期；2、更短的世代间隔；3、更高的基本再生数。这表明变异毒株奥密克戎有更为厉害的传染能力，疫情形势依然较为严峻。

Objective: To study the early epidemic development of the novel Coronavirus variant strain omicron as of 25 November, 2021, and on this basis to estimate the basic reproduction number of the epidemic caused by this variant strain as well as several important epidemiological parameters such as incubation period and generation interval.

Methods: Weibull distribution, Gamma distribution and Lognormal distribution were used to estimate the probability of incubation period and generation interval data obtained from the reported cases. Considering the general rules of the epidemic prevalence, the epidemic data from 16 to 25 November, 2021 were fitted using exponential growth model, and the value of basic regeneration number was estimated using exponential growth model and SEIR model respectively.

Results: As of November 25, 2021, the early epidemic data basically conform to the exponential growth, among which the index as of November 23, 2021 fitted well. The mean incubation distribution obtained by using Weibull distribution, Gamma distribution and lognormal distribution were 3.88, 3.87 and 3.88 days, and the mean generation intervals were 5.78, 5.81 and 5.82 days. The values ofR0

Conclusions: The novel Coronavirus variant omicron outbreak has following characteristics compared with those caused by the initial strain: 1. Shorter incubation period; 2. Shorter generation intervals; 3. Higher basic regeneration number. This indicates that the mutant strain omicron is more infectious and the situation remains serious.