Frontiers in Microbiology (Jul 2022)

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

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

DOI
https://doi.org/10.3389/fmicb.2022.912138
Journal volume & issue
Vol. 13

Abstract

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Severe acute respiratory syndrome-related coronavirus (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-RDTs) 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 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 RT-qPCR positive while SARS-CoV-2 Ag-RDT negative discordant results correlate with the absence 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 also verified in these samples. The data clearly demonstrate that a negative Ag-RDT sample is less likely to harbor infectious SARS-CoV-2 and, consequently, has a lower transmissible potential.

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