Shedding of infectious SARS-CoV-2 despite vaccination.

Authors :: Kasen K Riemersma
Luis A Haddock
Nancy A Wilson
Nicholas Minor
Jens Eickhoff
Brittany E Grogan
Amanda Kita-Yarbro
Peter J Halfmann
Hannah E Segaloff
Anna Kocharian
Kelsey R Florek
Ryan Westergaard
Allen Bateman
Gunnar E Jeppson
Yoshihiro Kawaoka
David H O'Connor
Thomas C Friedrich
Katarina M Grande
Source :: PLoS Pathogens, Vol 18, Iss 9, p e1010876 (2022)
Publication Year :: 2022
Publisher :: Public Library of Science (PLoS), 2022.
Abstract: The SARS-CoV-2 Delta Variant of Concern is highly transmissible and contains mutations that confer partial immune escape. The emergence of Delta in North America caused the first surge in COVID-19 cases after SARS-CoV-2 vaccines became widely available. To determine whether individuals infected despite vaccination might be capable of transmitting SARS-CoV-2, we compared RT-PCR cycle threshold (Ct) data from 20,431 test-positive anterior nasal swab specimens from fully vaccinated (n = 9,347) or unvaccinated (n = 11,084) individuals tested at a single commercial laboratory during the interval 28 June- 1 December 2021 when Delta variants were predominant. We observed no significant effect of vaccine status alone on Ct value, nor when controlling for vaccine product or sex. Testing a subset of low-Ct (