Asymptomatic COVID-19 Patients Can Contaminate Their Surroundings: an Environment Sampling Study

Wei L.,
Lin J.,
Duan X.,
Huang W.,
Lu X.,
Zhou J.,
Zong Z.
Document Type
Source Title
NLM (Medline)


The contamination of patients' surroundings by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains understudied. We sampled the surroundings and the air of six negative-pressure non-intensive care unit (non-ICU) rooms in a designated isolation ward in Chengdu, China, that were occupied by 13 laboratory-confirmed coronavirus disease 2019 (COVID-19) patients who had returned from overseas travel, including 2 asymptomatic patients. A total of 44 of 112 (39.3%) surface samples were positive for SARS-CoV-2 as detected by real-time PCR, suggesting extensive contamination, although all of the air samples were negative. In particular, in a single room occupied by an asymptomatic patient, four sites were SARS-CoV-2 positive, highlighting that asymptomatic COVID-19 patients do contaminate their surroundings and impose risks for others with close contact. Placement of COVID-19 patients in rooms with negative pressure may bring a false feeling of safety, and the importance of rigorous environment cleaning should be emphasized.IMPORTANCE Although it has been well recognized that the virus SARS-CoV-2, the causative agent of COVID-19, can be acquired by exposure to fomites, surprisingly, the contamination of patients' surroundings by SARS-CoV-2 is largely unknown, as there have been few studies. We performed an environmental sampling study for 13 laboratory-confirmed COVID-19 patients and found extensive contamination of patients' surroundings. In particular, we found that asymptomatic COVID-19 patients contaminated their surroundings and therefore imposed risks for other people. Environment cleaning should be emphasized in negative-pressure rooms. The findings may be useful to guide infection control practice to protect health care workers. Copyright © 2020 Wei et al.

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Index Keywords

asymptomatic infection; Betacoronavirus; Coronavirus infection; environment; environmental exposure; environmental microbiology; hazardous waste; human; isolation and purification; pandemic; pathology; procedures; virus pneumonia; Asymptomatic Infections; Betacoronavirus; Containment of Biohazards; Coronavirus Infections; Environment; Environmental Exposure; Environmental Microbiology; Humans; Pandemics; Pneumonia, Viral