The evidence of indirect transmission of SARS-CoV-2 reported in Guangzhou, China

Chaojun Xie,Jin Chen,Jun Yuan,Di Wu,Huide Peng,Yuzhou Gu,Xiao Zhang,Kuibiao Li,Xiaoxiao Lu,Lin Zhang,Hongjun Zhao,Jiachun Lu,Dahu Wang,Zhoubin Zhang

doi:10.1186/s12889-020-09296-y

Abstract

BackgroundMore than 2 months have passed since the novel coronavirus disease 2019 (COVID-19) first emerged in Wuhan, China. With the migration of people, the epidemic has rapidly spread within China and throughout the world. Due to the severity of the epidemic, undiscovered transmission of COVID-19 deserves further investigation. The aim of our study hypothesized possible modes of SARS-CoV-2 transmission and how the virus may have spread between two family clusters within a residential building in Guangzhou, China.MethodsIn a cross-sectional study, we monitored and traced confirmed patients and their close contacts from January 11 to February 5, 2020 in Guangzhou, China, including 2 family cluster cases and 61 residents within one residential building. The environmental samples of the building and the throat swabs from the patients and from their related individuals were collected for SARS-CoV-2 and tested with real-time reverse transcriptase polymerase chain reaction (RT-PCR). The relevant information was collected and reported using big data tools.ResultsThere were two notable family cluster cases in Guangzhou, which included 3 confirmed patients (family No.1: patient A, B, C) and 2 confirmed patients (family No.2: patient D, E), respectively. None of patients had contact with other confirmed patients before the onset of symptoms, and only patient A and patient B made a short stop in Wuhan by train. Home environment inspection results showed that the door handle of family No.1 was positive of SARS-CoV-2. The close contacts of the 5 patients all tested negative of SARS-CoV-2 and in good health, and therefore were released after the official medical observation period of 14-days. Finally, according to the traceability investigation through applying big data analysis, we found an epidemiological association between family No.1 and family No.2, in which patient D (family No.2) was infected through touching an elevator button contaminated by snot with virus from patient A (family No.1) on the same day.ConclusionsContaminants with virus from confirmed patients can pollute the environment of public places, and the virus can survive on the surface of objects for a short period of time. Therefore, in addition to the conventional droplet transmission, there is also indirect contact transmission such as snot-oral transmission that plays a crucial role in community spread of the virus.

Highlights

More than 2 months have passed since the novel coronavirus disease 2019 (COVID-19) first emerged in Wuhan, China
Characteristics of two family cluster cases In the cross-sectional study of COVID-19 in Guangzhou, we found that there were two notable family cluster cases, which included 3 and 2 cases of COVID-19 patients, respectively
The exposure The exposure is defined as the following situations within 14 days before the onset of illness applicable to individuals: 1) traveling to or living in Wuhan or other regions with severe epidemics abroad; 2) having contact with SARS-CoV-2 infected individuals whose nucleic acid test was positive or with patients who had fever or respiratory symptoms coming from Wuhan or other regions abroad that have been severely affected by the epidemic; 3) having been to 2 or more cases occurred fever or respiratory symptoms in a small area

Summary

Introduction

More than 2 months have passed since the novel coronavirus disease 2019 (COVID-19) first emerged in Wuhan, China. The aim of our study hypothesized possible modes of SARS-CoV-2 transmission and how the virus may have spread between two family clusters within a residential building in Guangzhou, China. In late December 2019, an outbreak of the novel coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was reported by the local health facilities in Wuhan, China [1, 2]. In order to elucidate the reason for the rapid spread of the disease, the researchers examined whether the virus could survive in external environment and found detectable nucleic acid of SARS-CoV-2 in environmental sample gathered from South China Seafood Market in Wuhan, the place where the virus first broke out. As reported in this study, there were two interesting family cluster cases reported in Guangzhou, providing the evidence of snot-oral indirect transmission of SARS-CoV-2

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