Detection and Isolation of Infectious SARS-CoV-2 Omicron Variants Collected from Residential Settings

WILLIAM VASS, Sripriya Nannu Shankar, John Lednicky, Carlos Manzanas, Yuetong Zhang, Jessica Boyette, Jiayi Chen, Yuqiao Chen, Amin Shirkhani, Mo Washeem, Yang Yang, Z. Hugh Fan, Arantzazu Eiguren-Fernandez, Chang-Yu Wu, University of Florida

     Abstract Number: 18
     Working Group: Bioaerosols

Abstract
Introduction:
Airborne transmission of infectious SARS-CoV-2 is increasingly accepted as the primary manner by which the virus is spread between people. Risk of inhalation exposure to the virus is high in enclosed and poorly ventilated spaces. We present a study focused on air sampling within residential environments occupied by individuals with COVID-19.

Method:
Air samplers (BioSpot-VIVAS, VIVAS, and BC-251) were positioned in primary- and secondary-occupancy regions in the homes of seven volunteers. Additionally, surface swab samples were collected from high-touch surfaces. Air and surface samples were processed by RT-qPCR. Isolation of SARS-CoV-2 in Vero E6 cells and LLC-MK2 cells was attempted for samples with detectable virus. Viable virus was quantified by plaque assay, and sequencing of SARS-CoV-2 was conducted for select samples according to the sampling day.

Results:
SARS-CoV-2 was detected in 24 of 128 samples (18.8%) by RT-qPCR and isolated from 14 (11.0%) in cell cultures. It was detected in 81.0% (17/21) and cultured from 61.9% (13/21) of samples that were collected using water condensation air samplers. No statistically significant differences existed in the likelihood of virus detection by RT-qPCR or amount of infectious virus in the air between areas of primary and secondary occupancy within residences. The SARS-CoV-2 isolated from all residences was determined by Sanger sequencing to belong to the omicron-lineage variant of concern.

Conclusions:
Our work provides information about the presence of SARS-CoV-2 in the air within homes of individuals with COVID-19. Information herein builds knowledge about the existence of infectious SARS-CoV-2 in the air. The demonstrated presence of virus beyond primary-occupancy spaces provides health agencies with information to apply to recommendations regarding airborne exposure risks in homes of sick individuals, such as enhancing air exchange rates, operating air purifiers, and using personal respiratory protection devices.