Clinical Significance of a High SARS-CoV-2 Viral Load in the Saliva

J Korean Med Sci. 2020 May 25;35(20):e195. doi: 10.3346/jkms.2020.35.e195.


Background: Patients with coronavirus disease 2019 (COVID-19) can unknowingly spread the virus to several people during the early subclinical period.

Methods: We evaluated the viral dynamics in various body fluid specimens, such as nasopharyngeal swab, oropharyngeal swab, saliva, sputum, and urine specimens, of two patients with COVID-19 from hospital day 1 to 9. Additional samples of the saliva were taken at 1 hour, 2 hours, and 4 hours after using a chlorhexidine mouthwash. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load was determined by real-time reverse transcriptase polymerase chain reaction (rRT-PCR).

Results: SARS-CoV-2 was detected from all the five specimens of both patients by rRT-PCR. The viral load was the highest in the nasopharynx (patient 1 = 8.41 log10 copies/mL; patient 2 = 7.49 log10 copies/mL), but it was also remarkably high in the saliva (patient 1 = 6.63 log10 copies/mL; patient 2 = 7.10 log10 copies/mL). SARS-CoV-2 was detected up to hospital day 6 (illness day 9 for patient 2) from the saliva of both patients. The viral load in the saliva decreased transiently for 2 hours after using the chlorhexidine mouthwash.

Conclusion: SARS-CoV-2 viral load was consistently high in the saliva; it was relatively higher than that in the oropharynx during the early stage of COVID-19. Chlorhexidine mouthwash was effective in reducing the SARS-CoV-2 viral load in the saliva for a short-term period.

Keywords: COVID-19; Chlorhexidine; SARS-CoV-2; Saliva; Viral Load.

Publication types

  • Case Reports

MeSH terms

  • Aged
  • Betacoronavirus / isolation & purification*
  • COVID-19
  • COVID-19 Testing
  • COVID-19 Vaccines
  • Clinical Laboratory Techniques
  • Coronavirus Infections / diagnosis
  • Coronavirus Infections / virology*
  • Female
  • Humans
  • Middle Aged
  • Pandemics
  • Pneumonia, Viral / virology*
  • SARS-CoV-2
  • Saliva / virology*
  • Viral Load*