Lin A, He ZB, Zhang S, Zhang JG, et al. Early risk factors for the duration of SARS-CoV-2 viral positivity in COVID-19 patients. Clin Infect Dis. 2020 Apr 27. pii: 5825508. doi: 10.1093.

Background: Pneumonia COVID-19 has became a pandemic. However, information on early risk factors for the duration of SARS-CoV-2 viral positivity is unavailable yet.

Methods: In this prospective study, a cohort of 137 patients with confirmed SARS-CoV-2 infection were enrolled. Clinical information and laboratory data were retrieved from electronic medical records. Viral positivity duration was calculated by an interval from the day SARS-CoV-2 positive confirmed to the day SARS-CoV-2 returned to negative in these 137 COVID-19 patients. Early risk factors for the duration of SARS-CoV-2 viral positivity were evaluated.

Findings: The median SARS-CoV-2 viral positivity duration is 12 days (range: 4 days ~ 45 days) for this cohort. Cox regression results showed a significantly shorter viral positivity duration was related to younger [hazard ratio (HR) = 0.658, p = 0.017], not severe patient (HR = 0.653, p = 0.076), higher count of lymphocytes (HR = 1.464, p = 0.033), eosinophils (HR = 1.514, p = 0.020) and CD8+ T cells (HR=1.745, p=0.033), and lower IL-6 (HR = 0.664, p = 0.036) and IL-10 (HR = 0.631, p = 0.021). Multivariate analysis with covariables adjusted results showed that the count of CD8+ T cells (HR=2.376, p=0.114) was a predominant risk factor for the SARS-CoV-2 viral positivity duration.

Interpretation: Our findings firstly provided early laboratory parameters such as count of CD8+ T cells, as risk factors for the duration of SARS-CoV-2 viral positivity, which have significance in control and prevention of the disease.