Increased close proximity airborne transmission of the SARS-CoV-2 Delta variant

Sci Total Environ. 2022 Apr 10;816:151499. doi: 10.1016/j.scitotenv.2021.151499. Epub 2021 Nov 6.


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.

Keywords: Airborne transmission; Close contact; Overdispersion; SARS-CoV-2 Delta variant.

MeSH terms

  • COVID-19*
  • Humans
  • SARS-CoV-2*

Supplementary concepts

  • SARS-CoV-2 variants