Characterization of Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant Shedding and Predictors of Viral Culture Positivity on Vaccinated Healthcare Workers With Mild Coronavirus Disease 2019

• Published in: The Journal of infectious diseases Vol. 226; no. 10; pp. 1726 - 1730
• Main Authors: Luna-Muschi, Alessandra, Noguera, Saidy Vásconez, Borges, Igor C, De Paula, Anderson V, Côrtes, Marina Farrel, Larocca, Carolina, Mari, Julia Ferreira, Guimarães, Lara Silva Pereira, Torres, Pablo Munoz, Scaccia, Nazareno, Villas-Boas, Lucy S, da Silva, Almir Ribeiro, Andrade, Pâmela S, Teixeira, Juliana C, Escadafal, Camille, de Oliveira, Vitor Falcão, Tozetto-Mendoza, Tania R, Mendes-Correa, Maria Cássia, Levin, Anna S, Sabino, Ester C, Costa, Silvia F
• Format: Journal Article
• Language: English
• Published: 11.11.2022
• ISSN: 0022-1899; 1537-6613
• DOI: 10.1093/infdis/jiac391

Abstract In this prospective cohort of 30 vaccinated healthcare workers with mild Omicron variant infection, we evaluated viral culture, rapid antigen test (RAT), and real-time reverse-transcription polymerase chain reaction (RT-PCR) of respiratory samples at days 5, 7, 10, and 14. Viral culture was positive in 46% (11/24) and 20% (6/30) of samples at days 5 and 7, respectively. RAT and RT-PCR (Ct ≤35) showed 100% negative predictive value (NPV), with positive predictive values (PPVs) of 32% and 17%, respectively, for predicting viral culture positivity. A lower RT-PCR threshold (Ct ≤24) improved culture prediction (PPV = 39%; NPV = 100%). Vaccinated persons with mild Omicron infection are potentially transmissible up to day 7. RAT and RT-PCR might be useful tools for shortening the isolation period.