Viral Load Kinetics of Severe Acute Respiratory Syndrome Coronavirus 2 in Hospitalized Individuals With Coronavirus Disease 2019

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) kinetics remain understudied, including the impact of remdesivir. In hospitalized individuals, peak sputum viral load occurred in week 2 of symptoms, whereas viremia peaked within 1 week of symptom-onset, suggesting early systemic seeding of SARS-CoV-2. Remdesivir treatment was associated with faster viral decay.

Keywords: COVID-19; SARS-CoV-2; remdesivir; viral kinetics; viral load.

Figure 1.

(A) Lines show the percentage of samples with detectable viral ribonucleic acid (RNA) for each compartment. Each point on the line represents the percentage of samples in the previous 7 days with detectable RNA, and the final point represents the proportion of detectable samples taken more than 28 days from symptom onset. Dots show individual viral load values for all sample types on the right axis. (B) The average rate of change in viral load over time given as the change in log₁₀ copies/mL per day for each sample compartment. Thirty-eight participants had 2 data points spaced between 7 and 14 days apart in at least 1 compartment and were included in this analysis. Sputum analysis included samples collected after 1 week of symptoms given the delayed peak in viral load. Wilcoxon rank-sum tests show no significant differences between any 2 groups. NP, nasopharyngeal; OP, oropharyngeal; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.

Figure 2.

Estimated rate of viral decay in all anatomical compartments per day in patients who did not receive remdesivir treatment and patients who did receive remdesivir treatment. The decay rate coefficient r has units of Day⁻¹ (ie, per day) to satisfy the implicitly nondimensional log₁₀-transformed regression equation: log₁₀(V) = Log₁₀(V₀) − rt. A Wilcoxon rank-sum test shows a significant difference in viral decay rates.