Saliva is a reliable and accessible source for the detection of SARS-CoV-2

• Main Authors: Luis A. Herrera, Alfredo Hidalgo-Miranda, Nancy Reynoso-Noverón, Abelardo A. Meneses-García, Alfredo Mendoza-Vargas, Juan P. Reyes-Grajeda, Felipe Vadillo-Ortega, Alberto Cedro-Tanda, Fernando Peñaloza, Emmanuel Frías-Jimenez, Cristian Arriaga-Canon, Rosaura Ruiz, Ofelia Angulo, Imelda López-Villaseñor, Carlos Amador-Bedolla, Diana Vilar-Compte, Patricia Cornejo, Mireya Cisneros-Villanueva, Eduardo Hurtado-Cordova, Mariana Cendejas-Orozco, José S. Hernández-Morales, Bernardo Moreno, Irwin A. Hernández-Cruz, César A. Herrera, Francisco García, Miguel A. González-Woge, Paulina Munguía-Garza, Fernando Luna-Maldonado, Antonia Sánchez-Vizcarra, Vincent G. Osnaya, Nelly Medina-Molotla, Yair Alfaro-Mora, Rodrigo E. Cáceres-Gutiérrez, Laura Tolentino-García, Patricia Rosas-Escobar, Sergio A. Román-González, Marco A. Escobar-Arrazola, Julio C. Canseco-Méndez, Diana R. Ortiz-Soriano, Julieta Domínguez-Ortiz, Ana D. González-Barrera, Diana I. Aparicio-Bautista, Armando Cruz-Rangel, Ana Paula Alarcón-Zendejas, Laura Contreras-Espinosa, Rodrigo González, Lissania Guerra-Calderas, Marco A. Meraz-Rodríguez, Michel Montalvo-Casimiro, Rogelio Montiel-Manríquez, Karla Torres-Arciga, Daniela Venegas, Vasti Juárez-González, Xiadani Guajardo-Barreto, Verónica Monroy-Martínez, Daniel Guillén, Jacquelina Fernández, Juliana Herrera, Renato León-Rodriguez, Israel Canela-Pérez, Blanca H. Ruíz-Ordaz, Rafael Valdez-Vazquez, Jennifer Bertin-Montoya, María Niembro-Ortega, Liudmila Villegas-Acosta, Daniela López-Castillo, Andrea Soriano-Ríos, Michael Gastelum-Ramos, Tonatiuh Zamora-Barandas, Jorge Morales-Baez, María García-Rodríguez, Mariano García-Martínez, Erik Nieto-Patlán, Maricarmen Quirasco-Baruch, Irma López-Martínez, Ernesto Ramírez-Gonzalez, Hiram Olivera-Díaz, Noe Escobar-Escamilla
• Format: Article
• Language: English
• Published: Elsevier 2021-04-01
• Series: International Journal of Infectious Diseases
• Subjects: COVID-19; SARS-CoV-2; Diagnostic test; Saliva testing; Pooling strategy
• Online Access: http://www.sciencedirect.com/science/article/pii/S1201971221000953

Objectives: The aim of this study was to investigate the feasibility of saliva sampling as a non-invasive and safer tool to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and to compare its reproducibility and sensitivity with nasopharyngeal swab samples (NPS). The use of sample pools was also investigated. Methods: A total of 2107 paired samples were collected from asymptomatic healthcare and office workers in Mexico City. Sixty of these samples were also analyzed in two other independent laboratories for concordance analysis. Sample processing and analysis of virus genetic material were performed according to standard protocols described elsewhere. A pooling analysis was performed by analyzing the saliva pool and the individual pool components. Results: The concordance between NPS and saliva results was 95.2% (kappa 0.727, p = 0.0001) and 97.9% without considering inconclusive results (kappa 0.852, p = 0.0001). Saliva had a lower number of inconclusive results than NPS (0.9% vs 1.9%). Furthermore, saliva showed a significantly higher concentration of both total RNA and viral copies than NPS. Comparison of our results with those of the other two laboratories showed 100% and 97% concordance. Saliva samples are stable without the use of any preservative, and a positive SARS-CoV-2 sample can be detected 5, 10, and 15 days after collection when the sample is stored at 4 °C. Conclusions: The study results indicate that saliva is as effective as NPS for the identification of SARS-CoV-2-infected asymptomatic patients. Sample pooling facilitates the analysis of a larger number of samples, with the benefit of cost reduction.