Molecular epidemiology of SARS-CoV-2 clusters caused by asymptomatic cases in Anhui Province, China
Related Experiment Video
Updated: Nov 27, 2025

Quantification and Whole Genome Characterization of SARS-CoV-2 RNA in Wastewater and Air Samples
Published on: June 30, 2023
Yuan Yuan1,2, Jun He1,2, Lei Gong1
1Anhui Provincial Center for Disease Control and Prevention, 12560, Fanhua Avenue, Hefei, China.
Background:
COVID-19 is a newly emerging disease caused by a novel coronavirus (SARS-CoV-2), which spread globally in early 2020. Asymptomatic carriers of the virus contribute to the propagation of this disease, and the existence of asymptomatic infection has caused widespread fear and concern in the control of this pandemic.
Methods:
In this study, we investigated the origin and transmission route of SARS-CoV-2 in Anhui's two clusters, analyzed the role and infectiousness of asymptomatic patients in disease transmission, and characterized the complete spike gene sequences in the Anhui strains.
Results:
We conducted an epidemiological investigation of two clusters caused by asymptomatic infections sequenced the spike gene of viruses isolated from 12 patients. All cases of the two clusters we investigated had clear contact histories, both from Wuhan, Hubei province. The viruses isolated from two outbreaks in Anhui were found to show a genetically close link to the virus from Wuhan. In addition, new single nucleotide variations were discovered in the spike gene.
Conclusions:
Both clusters may have resulted from close contact and droplet-spreading and asymptomatic infections were identified as the initial cause. We also analyzed the infectiousness of asymptomatic cases and the challenges to the current epidemic to provided information for the development of control strategies.
Related Concept Videos
Single Nucleotide Polymorphisms-SNPs
Genome-wide Association Studies-GWAS
GWAS does not require the identification of the target gene involved in...
Viral Mutations
Causality in Epidemiology

