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.
Keywords: SARS-CoV-2; antigen rapid test; infectious virus detection; qRT- PCR; virus transmissibility.
Copyright © 2022 Corrêa, Faffe, Galliez, Gonçalves, Maia, da Silva, Moreira, Mariani, Campos, Leitão, de Souza, Cunha, Nascimento, Ribeiro, da Cruz, Policarpo, Gonzales, Rodgers, Berg, Vijesurier, Cloherty, Hackett Jr., Ferreira Jr., Castiñeiras, Tanuri and da Costa.