SARS-CoV-2 viral load in nasopharyngeal swabs is not an independent predictor of unfavorable outcome
Authors: Salto-Alejandre Sonsoles , Berastegui-Cabrera Judith , Camacho-Martínez Pedro , Infante-Domínguez Carmen , Carretero-Ledesma Marta , Crespo-Rivas Juan Carlos , Márquez Eduardo , Lomas José Manuel , Bueno Claudio , Amaya Rosario , Lepe José Antonio , Cisneros José Miguel , Pachón Jerónimo , Cordero Elisa , Sánchez-Céspedes Javier ,   The Virgen del Rocío Hospital COVID-19 Working Team, Cisneros José Miguel , Aguilar-Guisado Manuela , Aguilera Almudena , Aguilera Clara , Aldabo-Pallas Teresa , Alfaro-Lara Verónica , Amodeo Cristina , Ampuero Javier , Avilés María Dolores , Asensio Maribel , Barón-Franco Bosco , Barrera-Pulido Lydia , Bellido-Alba Rafael , Bernabeu-Wittel Máximo , Caballero-Eraso Candela , Cabrera Macarena , Calderón Enrique , Carbajal-Guerrero Jesús , Cid-Cumplido Manuela , Corcia-Palomo Yael , Delgado Juan , Domínguez-Petit Antonio , Deniz Alejandro , Dusseck-Brutus Reginal , Escoresca-Ortega Ana , Espinosa Fátima , Espinosa Nuria , Espinoza Michelle , Ferrándiz-Millón Carmen , Ferrer Marta , Ferrer Teresa , Gallego-Texeira Ignacio , Gámez-Mancera Rosa , García Emilio , García-Delgado Horacio , García-Gutiérrez Manuel , Gascón-Castillo María Luisa , González-Estrada Aurora , González Demetrio , Gómez-González Carmen , González-León Rocío , Grande-Cabrerizo Carmen , Gutiérrez Sonia , Hernández-Quiles Carlos , Herrera-Melero Inmaculada Concepción , Herrero-Romero Marta , Jara Luis , Jiménez-Juan Carlos , Jiménez-Jorge Silvia , Jiménez-Sánchez Mercedes , Lanseros-Tenllado Julia , López Carmina , López Isabel , López-Barrios Álvaro , López-Cortés Luis F. , Luque-Márquez Rafael , Macías-García Daniel , Martín-Gutiérrez Guillermo , Martín-Villén Luis , Molina José , Morillo Aurora , Navarro-Amuedo María Dolores , Nieto-Martín Dolores , Ortega Francisco , Paniagua-García María , Peña-Rodríguez Amelia , Pérez Esther , Poyato Manuel , Praena-Segovia Julia , Ríos Rafaela , Roca-Oporto Cristina , Rodríguez Jesús F. , Rodríguez-Hernández María Jesús , Rodríguez-Suárez Santiago , Rodríguez-Villodres Ángel , Romero-Rodríguez Nieves , Ruiz Ricardo , de Azua Zaida Ruiz , Salamanca Celia , Sánchez Sonia , Sánchez-Montagut Víctor Manuel , Sotomayor César , Benjumea Alejandro Suárez , Toral Javier 
Published: June 2021

The aim was to assess the ability of nasopharyngeal SARS-CoV-2 viral load at first patient’s hospital evaluation to predict unfavorable outcomes. We conducted a prospective cohort study including 321 adult patients with confirmed COVID-19 through RT-PCR in nasopharyngeal swabs. Quantitative Synthetic SARS-CoV-2 RNA cycle threshold values were used to calculate the viral load in log10 copies/mL. Disease severity at the end of follow up was categorized into mild, moderate, and severe. Primary endpoint was a composite of intensive care unit (ICU) admission and/or death (n = 85, 26.4%). Univariable and multivariable logistic regression analyses were performed. Nasopharyngeal SARS-CoV-2 viral load over the second quartile (≥ 7.35 log10 copies/mL, p = 0.003) and second tertile (≥ 8.27 log10 copies/mL, p = 0.01) were associated to unfavorable outcome in the unadjusted logistic regression analysis. However, in the final multivariable analysis, viral load was not independently associated with an unfavorable outcome. Five predictors were independently associated with increased odds of ICU admission and/or death: age ≥ 70 years, SpO2, neutrophils > 7.5 × 103/µL, lactate dehydrogenase ≥ 300 U/L, and C-reactive protein ≥ 100 mg/L. In summary, nasopharyngeal SARS-CoV-2 viral load on admission is generally high in patients with COVID-19, regardless of illness severity, but it cannot be used as an independent predictor of unfavorable clinical outcome.