The correlation between viral shedding duration and blood biomarkers in COVID-19-infected patients

Abstract

Background: Since December 2019, the world is struggling with an outbreak of coronavirus disease-2019 (COVID-19) infection mostly represented as an acute respiratory distress syndrome and has turned into the most critical health issue worldwide. Limited information is available about the association between dynamic changes in the naso/oropharyngeal viral shedding in infected patients and biomarkers, aiming to be assessed in the current study.

Materials and methods: This quasi-cohort study was conducted on 31 patients with moderate severity of COVID-19 manifestations, whose real-time polymerase chain reaction (RT-PCR) test was positive for severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) RNA at baseline. RT-PCR was rechecked for patients every 3-4 days until achieving two negative ones. In parallel, biomarkers, including lymphocyte count, lactate dehydrogenase (LDH), and C-reactive protein (CRP), were assessed every other day, as well. Viral shedding also was assessed.

Results: Spearman's correlation test revealed a significant direct correlation between the viral shedding from the symptom onset and the time, in which CRP (P = 0.0015, r = 0.54) and LDH (P = 0.001, r = 0.6207) return to normal levels after symptom onset, but not for lymphocyte count (P = 0.068, r = 0.34).

Conclusion: Based on the current study's findings, the duration of SARS-CoV-2 RNA shedding was directly correlated with the required time for LDH and CRP return to normal levels. Therefore, these factors can be considered the determinants for patients' discharge, isolation, and return to social activities; however, further investigations are required to generalize the outcomes.

Keywords: C-reactive protein; COVID-19; lymphocyte count; real-time polymerase chain reaction; virus shedding.