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Updated: Oct 14, 2025

Quantification and Whole Genome Characterization of SARS-CoV-2 RNA in Wastewater and Air Samples
Published on: June 30, 2023
Increased close proximity airborne transmission of the SARS-CoV-2 Delta variant
Alex Mikszewski1, Luca Stabile2, Giorgio Buonanno3
1International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Qld, Australia; CIUS Building Performance Lab, The City University of New York, New York 10001, NY, USA.
Abstract:
The Delta variant of SARS-CoV-2 causes higher viral loads in infected hosts, increasing the risk of close proximity airborne transmission through breathing, speaking and coughing. We performed a Monte Carlo simulation using a social contact network and exponential dose-response model to quantify the close proximity reproduction number of both wild-type SARS-CoV-2 and the Delta variant. We estimate more than twice as many Delta variant cases will reproduce infection in their close proximity contacts (64%) versus the wild-type SARS-CoV-2 (29%). Occupational health guidelines must consider close proximity airborne transmission and recommend improved personal respiratory protection for high-risk workers.
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