Factors associated with viral clearance periods from patients with COVID-19: A retrospective observational cohort study

Abstract

Introduction: Knowledge is limited on the virologic course of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, particularly the time taken for viral clearance and the optimal time to discontinue isolation. This study aims to identify the clinical and demographic factors influencing the time taken for viral clearance in patients with COVID-19 to determine the optimal isolation period. Methods: This two-center retrospective observational cohort study was conducted between March 1 and June 31, 2020. Patients with COVID-19, which was confirmed by real-time reverse transcription polymerase chain reaction, were included. Data were extracted from medical records. The positive duration, which was defined as the period from the day of symptom onset to the negative conversion day, was assessed using a generalized linear model. Results: We included 63 patients. The mean positive duration was 20 days. The positive duration was significantly shorter for patients younger than 30 years of age and those between 30 and 60 years of age than for patients older than 60 years of age. We observed a more scattered distribution of the positive duration in older patients than in younger patients. Conclusions: Younger patients who recovered from COVID-19 took less time to clear SARS-CoV-2 than older patients; thus, a classification of the isolation periods based on age could be considered. A uniform viral clearance period for older patients may be difficult to determine because of biases such as underlying medical conditions. Further surveillance measures are recommended to determine the viral clearance time and the optimal isolation period.

COVID-19 patient characteristics and time to viral clearance: A retrospective observational study in a multiethnic population (United Arab Emirates)

“…Our study revealed that advanced age was associated with an increased risk of prolonged time to viral clearance, which is consistent with previous studies [ 19 , 22 , 23 ]. This could be attributed to the decline of T cell functions and proliferation with increasing age resulting in decreased control of viral replication and viral clearance.…”

“…In Xu et al's study [11,p.799–806], the severity of COVID-19 at admission was significantly associated with prolonged viral shedding. Time to viral clearance was also shorter among patients with mild symptoms compared with severe symptoms [22] . Zhou et al [6,p.1054–1062] also reported prolonged time till viral clearance among severe and critically ill COVID-19 patients.…”

“…Interestingly, they showed a significantly longer time until viral clearance. Previous reports had reported higher viral load in asymptomatic COVID-19 patients, and it decreased slowly compared with symptomatic patients [ 22 , 29 ]. However, the positivity of viral detection does not always confirm transmissibility and being infectious; also, false-positive results could occur.…”

Factors associated with prolonged duration of viral clearance in non-severe SARS-CoV-2 patients in Osaka, Japan

“…Our findings were similar to those of a small Japanese study of 63 patients treated at hospitals in Nara Prefecture (median age 47 [SD 19.9]). This study reported a viral clearance period of 20 days [ 20 ].…”

To study duration of viral clearance in COVID 19 patients: A Prospective study from Bangalore, India

“…Hirai et al, observed that the younger patients who recovered from COVID-19 took less time to clear SARS-CoV-2 compared to the elderly patients; thus, a classification of the isolation periods based on age could be considered. 8 Male 62.14% in Group1, 71.9% in Group 2, 83.3% in Group3, Female 37.8% in Group 1, 28.10% in Group 2, 16.67% in Group 3 respectively (Figure 1).…”