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SARS-CoV-2 in Residential Rooms of Two Self-Isolating Young Persons with COVID-19
SRIPRIYA NANNU SHANKAR, Chiran Witanachchi, Alyssa Morrea, John Lednicky, Julia Loeb, Md. Mahbubul Alam, Z. Hugh Fan, Arantzazu Eiguren-Fernandez, Chang-Yu Wu, University of Florida
Abstract Number: 93
Working Group: Bioaerosols
Abstract
Individuals with COVID-19 have generally been advised to self-isolate at their residences, unless they need medical attention. Epidemiological data and contact tracing suggest that airborne transmission of SARS-CoV-2 leads to outbreaks in residential settings. However, environmental monitoring for the detection of virus in such settings are limited. We present a pilot study on environmental sampling for SARS-CoV-2 virions in the residential rooms of two self-quarantined volunteers with COVID-19. Apart from standard surface swab sampling, different air samplers positioned 0.3-2.2 m from the volunteers were used: inline air samplers with polytetrafluoroethylene (PTFE) filters, VIable Virus Aerosol Sampler, NIOSH 2-stage cyclone sampler, and Sioutas personal cascade impactor sampler. SARS-CoV-2 RNA was detected in one air sample from volunteer A’s room with a rRT-qPCR quantitation cycle (Cq) of 38.21 for the SARS-CoV-2 N-gene, indicating a low amount of airborne virus. In contrast, the samples collected from volunteer B’s room yielded Cq values ranging from 14.58 to 31.13 in various air and surface samples, indicating that this volunteer was actively shedding relatively high amounts of SARS-CoV-2. Despite Cq values of 34-37 in rRT-qPCR analyses of vRNA purified from the cell culture medium inoculated with samples from volunteer B’s room, attempts to isolate SARS-CoV-2 in cell culture were unsuccessful, due to out-competition by a co-infecting Human adenovirus B3 (HAdVB3) that killed the Vero E6 cell cultures within 4 days of their inoculation. The size distribution of SARS-CoV-2 containing particles collected from the air of volunteer B's room was in the range <0.25 µm to >4.4 µm, suggesting a risk of aerosol transmission. The detection of virus in surface samples also underscores the potential for fomite transmission of SARS-CoV-2 in indoor settings. Following CDC guidelines for hygienic practices and limiting contact with an infected individual are recommended for reducing infection risks in residential settings.