AUTHOR=Corrêa Isadora Alonso , Faffe Débora Souza , Galliez Rafael Mello , Gonçalves Cássia Cristina Alves , Maia Richard Araújo , da Silva Gustavo Peixoto , Moreira Filipe Romero Rebello , Mariani Diana , Campos Mariana Freire , Leitão Isabela de Carvalho , de Souza Marcos Romário , Cunha Marcela Sabino , Nascimento Érica Ramos dos Santos , Ribeiro Liane de Jesus , da Cruz Thais Felix Cordeiro , Policarpo Cintia , Gonzales Luis , Rodgers Mary A. , Berg Michael , Vijesurier Roy , Cloherty Gavin A. , Hackett John , Ferreira Orlando da Costa , Castiñeiras Terezinha Marta Pereira Pinto , Tanuri Amilcar , da Costa Luciana Jesus 

TITLE=A SARS-CoV-2 Negative Antigen Rapid Diagnostic in RT-qPCR Positive Samples Correlates With a Low Likelihood of Infectious Viruses in the Nasopharynx

JOURNAL=Frontiers in Microbiology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.912138

DOI=10.3389/fmicb.2022.912138

ISSN=1664-302X

ABSTRACT=SARS-CoV-2 transmission occurs even among fully vaccinated individuals; thus, prompt identification of infected patients is central to control viral circulation. Antigen rapid diagnostic tests (Ag-RDT) are highly specific, but sensitivity is variable. Discordant RT- qPCR vs Ag-RDT results are reported, raising the question of whether negative Ag-RDT in positive RT-qPCR samples could imply the absence of infectious viruses. To study the relationship between a negative Ag-RDT results with virological, molecular, and serological parameters, we selected a cross sectional and a follow-up dataset and analyzed virus culture, subgenomic RNA quantification, and sequencing to determine infectious viruses and mutations. We demonstrated that a positive SARS-CoV-2 Ag-RDT result correlates with the presence of infectious virus in nasopharyngeal samples. A decrease in sgRNA detection together with an expected increase in detectable anti-S and anti-N IgGs was verified in negative Ag-RDT / positive RT-qPCR samples. The data clearly demonstrates the less likelihood of a negative Ag-RDT sample to harbour infectious SARS-CoV-2 and consequently with a lower transmissible potential.