SARS-CoV-2 identification and IgA antibodies in saliva: One sample two tests approach for diagnosis

A. Aita, D. Basso, A. Cattelan, P. Fioretto, F. Navaglia, F. Barbaro, Alice Stoppa, Enrico Coccorullo, Assunta Farella, Aurora Socal, R. Vettor, M. Plebani

Clinica Chimica Acta, 2020

Aim This study aims to verify whether standardized saliva collection is suitable for SARS-CoV-2 molecular detection and IgA measurement. Methods 43 COVID-19 inpatients and 326 screening subjects underwent naso-pharyngeal (NP)-swab and saliva collection (Salivette). Inpatients also underwent repeated blood collections to evaluate inflammation and organs involvement. In all patients and subjects, SARS-CoV-2 (gene E) rRT-PCR was undertaken in saliva and NP-swabs. Salivary IgA and serum IgA, IgG, IgM were measured on inpatients’ samples. Results NP-swabs and saliva were both SARS-CoV-2 positive in 7 (16%) or both negative in 35 (82%) out of 43 patients successfully included in the study. NP-swabs and saliva results did not perfectly match in one patient (saliva positive, NP-swab negative). Positive molecular results were significantly associated with disease duration (p=0.0049). 326/326 screening subjects were SARS-CoV-2 negative on both NP-swabs and saliva. Among the 27 saliva samples tested for IgA, 18 were IgA positive. Salivary IgA positivity was associated with pneumonia (p=0.002) and CRP values (p=0.0183), not with other clinical and molecular data, or with serum immunoglubulins. Conclusions A standardized saliva collection can be adopted to detect SARS-CoV-2 infection in alternative to NP-swabs. Preliminary data on salivary IgA support the use of saliva also for patient monitoring.

Cited by 21 publications.

Field of study: Medicine

10.1016/j.cca.2020.09.018