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COVID-19 salivary signature: diagnostic and research opportunities
  1. Dipak Sapkota1,
  2. Tine Merete Søland1,2,
  3. Hilde Kanli Galtung1,
  4. Lars Peter Sand1,
  5. Simone Giannecchini3,
  6. Kelvin K W To4,5,6,
  7. Maria Cassia Mendes-Correa7,
  8. Daniel Giglio8,
  9. Bengt Hasséus9,10,
  10. Paulo Henrique Braz-Silva7,11
  1. 1 Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
  2. 2 Department of Pathology, Rikshospitalet University Hospital, Oslo, Norway
  3. 3 Department of Experimental and Clinical Medicine, Universita degli Studi di Firenze, Firenze, Toscana, Italy
  4. 4 State Key Laboratory for Emerging Infectious Diseases, Department of Microbiology, Li KaShing Faculty of Medicine of the University of Hong Kong, Hong Kong, China
  5. 5 Department of Microbiology, Queen Mary Hospital, Hong Kong, China
  6. 6 Department of Clinical Microbiology and Infection Control, The University of Hong Kong – Shenzhen Hospital, Shenzhen, China
  7. 7 Laboratory of Virology (LIM-52), Institute of Tropical Medicine of São Paulo, School of Medicine, University of São Paulo, São Paulo, Brazil
  8. 8 Department of Clinical Oncology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
  9. 9 Department of Oral Medicine and Pathology, Institute of Odontology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
  10. 10 Clinic of Oral Medicine, Region Västra Götaland, Gothenburg, Sweden
  11. 11 Department of Stomatology, School of Dentistry, University of São Paulo, São Paulo, Brazil
  1. Correspondence to Professor Paulo Henrique Braz-Silva, Division of General Pathology, Department of Stomatology, Universidade de Sao Paulo Faculdade de Odontologia, Sao Paulo, Brazil; pbraz{at}; Professor Dipak Sapkota, Department of Oral Biology, Faculty of Dentistry, Oslo, Norway; dipak.sapkota{at}


The COVID-19 (caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)) epidemic started in Wuhan (Hubei Province, China) in mid-December 2019 and quickly spread across the world as a pandemic. As a key to tracing the disease and to implement strategies aimed at breaking the chain of disease transmission, extensive testing for SARS-CoV-2 was suggested. Although nasopharyngeal/oropharyngeal swabs are the most commonly used biological samples for SARS-CoV-2 diagnosis, they have a number of limitations related to sample collection and healthcare personnel safety. In this context, saliva is emerging as a promising alternative to nasopharyngeal/oropharyngeal swabs for COVID-19 diagnosis and monitoring. Saliva collection, being a non-invasive approach with possibility for self-collection, circumvents to a great extent the limitations associated with the use of nasopharyngeal/oropharyngeal swabs. In addition, various salivary biomarkers including the salivary metabolomics offer a high promise to be useful for better understanding of COVID-19 and possibly in the identification of patients with various degrees of severity, including asymptomatic carriers. This review summarises the clinical and scientific basis for the potential use of saliva for COVID-19 diagnosis and disease monitoring. Additionally, we discuss saliva-based biomarkers and their potential clinical and research applications related to COVID-19.

  • diagnostic techniques and procedures
  • infections
  • molecular biology
  • salivary glands
  • virology

This article is made freely available for use in accordance with BMJ’s website terms and conditions for the duration of the covid-19 pandemic or until otherwise determined by BMJ. You may use, download and print the article for any lawful, non-commercial purpose (including text and data mining) provided that all copyright notices and trade marks are retained.

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  • Handling editor Tahir S Pillay.

  • Contributors DS, SG, BH and PHB-S contributed to conception, design, data interpretation and drafted the manuscript; TMS, HKG, LPS, KKWT, MCM-C and DG contributed to design and data interpretation, critically revised the manuscript. All authors gave their final approval and agreed to be accountable for all aspects of the work.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.