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Comparison of Epidemiological Characteristics and Transmissibility of Different Strains of COVID-19 Based on the Incidence Data of All Local Outbreaks in China as of March 1, 2022

35 Pages Posted: 7 Apr 2022

See all articles by Niu Yan

Niu Yan

Chinese Center for Disease Control and Prevention

Li Luo

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Shiting Yang

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Guzainuer Abudurusuli

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Nijuan Xiang

Chinese Center for Disease Control and Prevention

Lei Zhou

Chinese Center for Disease Control and Prevention

Rui Wang

Chinese Center for Disease Control and Prevention

Ruiqi Ren

Chinese Center for Disease Control and Prevention

Chao Li

Chinese Center for Disease Control and Prevention

Xiaoye Wang

Chinese Center for Disease Control and Prevention

Dan Li

Chinese Center for Disease Control and Prevention

Zeyu Zhao

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Jia Rui

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Zhuoyang Li

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Bin Deng

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Weikang Liu

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Zhe Zhang

Shandong University - School of Basic Medical Sciences

Kangguo Li

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Chan Liu

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Peihua Li

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Jiefeng Huang

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Tianlong Yang

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Yao Wang

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Tianmu Chen

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Qun Li

Chinese Center for Disease Control and Prevention

More...

Abstract

Background: The epidemiological characteristics and transmissibility of Coronavirus Disease 2019 (COVID-19) may undergo changes due to the mutation of Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) strains. The purpose of this study is to compare the differences in the outbreaks of the different strains, with regards to aspects such as epidemiological characteristics, transmissibility, and difficulties in prevention and control.

Methods: COVID-19 data from outbreaks of pre-Delta strains, the Delta variant and Omicron variant, were obtained from the Chinese Center for Disease Control and Prevention (CDC). Case data were collected from China’s direct-reporting system, and the data concerning outbreaks were collected by on-site epidemiological investigators and collated by the authors of this paper. Indicators such as the effective reproduction number (Reff), time-dependent reproduction number (Rt), rate of decrease in transmissibility (RDT), and duration from the illness onset date to the diagnosed date (DID) / reported date (DIR) were used to compare differences in transmissibility between pre-Delta strains, Delta variants and Omicron variants. A nonparametric test was used to compare differences in epidemiological characteristics and transmissibility between outbreaks of different strains. P < 0.05 indicated that the difference was statistically significant.

Results: Mainland China has maintained a “dynamic zero-out strategy” since the first case was reported, and clusters of outbreaks have occurred intermittently. The strains causing outbreaks in mainland China have gone through three stages: the outbreak of pre-Delta strains, the outbreak of the Delta variant, and outbreaks involving the superposition of Delta and Omicron variant strains. Each outbreak of pre-Delta strains went through two stages: a rising stage and a falling stage; Each outbreak of the Delta variant and Omicron variant went through three stages: a rising stage, a platform stage and a falling stage. The maximum Reff value of Omicron variant outbreaks was highest (median: 6.7; ranged from 5.3 to 8.0) and the differences were statistically significant. The RDT value of outbreaks involving pre-Delta strains was smallest (median: 91.4%; [IQR]: 87.30%-94.27%), and the differences were statistically significant. The DID and DIR of all strains accounted for the most in 0 ~ 2 days, with more than 75%. The range of duration for outbreaks of pre-Delta strains was the largest (median: 20 days, ranging from 1 to 61 days), and the differences were statistically significant.

Conclusion: With the evolution of the virus, the transmissibility of the variants has increased. The transmissibility of the Omicron variant is higher than that of both the pre-Delta strains and the Delta variant, and is more difficult to suppress. These findings enable us to get a more clear and precise picture of the transmissibility of the different variants in the real world, in accordance with the findings of previous studies. Reff is more suitable than Rt for assessing the transmissibility of the disease during an epidemic outbreak.

Funding Information: This study was partly supported by the COVID-19 Emergency and Pandemic Response Program (Grant INV-005832); The National Key Research and Development Program (2021YFC2301604).

Declaration of Interests: The authors declare no conflicts of interests.

Suggested Citation

Yan, Niu and Luo, Li and Yang, Shiting and Abudurusuli, Guzainuer and Xiang, Nijuan and Zhou, Lei and Wang, Rui and Ren, Ruiqi and Li, Chao and Wang, Xiaoye and Li, Dan and Zhao, Zeyu and Rui, Jia and Li, Zhuoyang and Deng, Bin and Liu, Weikang and Zhang, Zhe and Li, Kangguo and Liu, Chan and Li, Peihua and Huang, Jiefeng and Yang, Tianlong and Wang, Yao and Chen, Tianmu and Li, Qun, Comparison of Epidemiological Characteristics and Transmissibility of Different Strains of COVID-19 Based on the Incidence Data of All Local Outbreaks in China as of March 1, 2022 (4/4/2022). Available at SSRN: https://ssrn.com/abstract=4077168 or http://dx.doi.org/10.2139/ssrn.4077168

Niu Yan

Chinese Center for Disease Control and Prevention

155 Changbai Road
Changping District
Beijing, Changping District 102206
China

Li Luo

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Xiamen
China

Shiting Yang

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Xiamen
China

Guzainuer Abudurusuli

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Nijuan Xiang

Chinese Center for Disease Control and Prevention

Lei Zhou

Chinese Center for Disease Control and Prevention

Rui Wang

Chinese Center for Disease Control and Prevention

Ruiqi Ren

Chinese Center for Disease Control and Prevention

Chao Li

Chinese Center for Disease Control and Prevention

Xiaoye Wang

Chinese Center for Disease Control and Prevention

Dan Li

Chinese Center for Disease Control and Prevention

Zeyu Zhao

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Xiamen
China

Jia Rui

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Zhuoyang Li

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics ( email )

Xiamen
China

Bin Deng

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Xiamen
China

Weikang Liu

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics ( email )

Xiamen
China

Zhe Zhang

Shandong University - School of Basic Medical Sciences

Kangguo Li

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Chan Liu

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Xiamen
China

Peihua Li

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics ( email )

Xiamen
China

Jiefeng Huang

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics ( email )

Xiamen
China

Tianlong Yang

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics ( email )

Xiamen
China

Yao Wang

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics

Xiamen
China

Tianmu Chen

Xiamen University - State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics ( email )

Xiamen
China
+86-13661934715 (Phone)

Qun Li (Contact Author)

Chinese Center for Disease Control and Prevention ( email )

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