Association between salivary SARS-CoV-2 viral load and acute and late symptoms of COVID-19 in non- hospitalized patients: A cohort study

Background: The clinical course of COVID-19 can be divided into two phases: acute and late. Aims: This study evaluated the association between salivary SARS-CoV-2 load and acute and late symptoms of COVID-19 in non-hospitalized patients. Methods: This cohort study included 109 participants who tested positive for SARS-CoV-2 in a rapid antigen test (Ethics Committee, 4.434.828). Saliva samples were obtained and acute symptoms were recorded immediately after the diagnosis of COVID-19. Late symptoms were recorded 3 months later. The viral load was estimated based on real-time reverse transcription polymerase chain reaction (qRT-PCR) cycle threshold (Ct). The chi-square and Student t test were used to assess the association between salivary viral load and symptoms (p ≤ 0.05). Results: A lower salivary viral load was associated with diarrhea (RR = 0.73, 95% CI = 0.55–0.97, p = 0.04), anosmia (RR = 0.63, 95% CI = 0.47–0.84, p = 0.002), and dysgeusia (RR = 0.69, 95% CI = 0.52–0.91, p = 0.01) in the acute phase of the infection. Regarding late symptoms, a lower viral load remained associated with anosmia (RR = 0.68, 95% CI = 0.51–0.90, p = 0.05) and dysgeusia (RR = 0.59, 95% CI = 0.50–0.70, p = 0.03). Conclusion: Lower viral load is a known marker of mild COVID-19. The association of lower viral load with anosmia and dysgeusia in the acute and late phases of the disease and with diarrhea in the acute phase suggests that these symptoms are predictive of mild COVID-19.