A Novel Saliva RT-LAMP Workflow for Rapid Identification of COVID-19 Cases and Restraining Viral Spread

Author(s):Show less -

Kobayashi, Gerson Shigeru ^[1] ; Brito, Luciano Abreu ^[1] ; Moreira, Danielle de Paula ^[1] ; Suzuki, Angela May ^[1] ; Ping Hsia, Gabriella Shih ^[1] ; Pimentel, Lylyan Fragoso ^[1] ; Barreto de Paiva, Ana Paula ^[1] ; Dias, Carolina Regoli ^[1] ; Vilaca Lourenco, Naila Cristina ^[1] ; Oliveira, Beatriz Araujo ^[2] ; Manuli, Erika Regina ^[2] ; Corral, Marcelo Andreetta ^[1] ; Cavacana, Natale ^[1] ; Mitne-Neto, Miguel ^[3] ; Sales, Maria Mirtes ^[4] ; Dell' Aquila, Luiz Phellipe ^[4] ; Razuk Filho, Alvaro ^[4] ; Parrillo, Eduardo Fagundes ^[4] ; Mendes-Correa, Maria Cassia ^[2] ; Sabino, Ester Cerdeira ^[2] ; Costa, Silvia Figueiredo ^[2] ; Leal, Fabio Eudes ^[5] ; Sgro, German Gustavo ^{[6, 7]} ; Farah, Chuck Shaker ^[6] ; Zatz, Mayana ^[1] ; Passos-Bueno, Maria Rita ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Biociencias, Ctr Pesquisa Genoma Humano & Celulas Tronco HUG C, BR-05508090 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Inst Med Trop, BR-05403000 Sao Paulo - Brazil

^[3] Grp Fleury, Res & Dev, BR-04344070 Sao Paulo - Brazil

^[4] Inst Ensino & Pesquisa Prevent Senior, BR-04547100 Sao Paulo - Brazil

^[5] Univ Municipal Sao Caetano do Sul USCS, Fac Med, BR-09521160 Sao Paulo - Brazil

^[6] Univ Sao Paulo, Inst Quim, BR-05508000 Sao Paulo - Brazil

^[7] Univ Sao Paulo, Fac Ciencias Farmaceut Ribeirao Preto, BR-14040903 Ribeirao Preto - Brazil

• Document type: Journal article
• Source: DIAGNOSTICS; v. 11, n. 8 AUG 2021.
• Web of Science Citations: 0

Abstract

Rapid diagnostics is pivotal to curb SARS-CoV-2 transmission, and saliva has emerged as a practical alternative to naso/oropharyngeal (NOP) specimens. We aimed to develop a direct RT-LAMP (reverse transcription loop-mediated isothermal amplification) workflow for viral detection in saliva, and to provide more information regarding its potential in curbing COVID-19 transmission. Clinical and contrived specimens were used to optimize formulations and sample processing protocols. Salivary viral load was determined in symptomatic patients to evaluate the clinical performance of the test and to characterize saliva based on age, gender and time from onset of symptoms. Our workflow achieved an overall sensitivity of 77.2% (n = 90), with 93.2% sensitivity, 97% specificity, and 0.895 Kappa for specimens containing >10(2) copies/ mu L (n = 77). Further analyses in saliva showed that viral load peaks in the first days of symptoms and decreases afterwards, and that viral load is similar to 10 times lower in females compared to males, and declines following symptom onset. NOP RT-PCR data did not yield relevant associations. This work suggests that saliva reflects the transmission dynamics better than NOP specimens, and reveals gender differences that may reflect higher transmission by males. This saliva RT-LAMP workflow can be applied to track viral spread and, to maximize detection, testing should be performed immediately after symptoms are presented, especially in females. (AU)

• FAPESP's process: 13/08028-1 - CEGH-CEL - Human Genome and Stem Cell Research Center
• Grantee: Mayana Zatz
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 20/05949-2 - Rapid, low-cost and efficient molecular diagnostics and large-scale population testing strategies for COVID-19 management
• Grantee: Mayana Zatz
• Support Opportunities: Regular Research Grants