Introduction
Since the outbreak in December 2019, coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has given rise to a worldwide pandemic(Li et al., 2020). As of December 13, 2020, 70 million COVID-19 cases and 1.6 million deaths have been reported globally(WHO, 2020). At the same time, tens of millions of patients with COVID-19 have recovered and been discharged from the hospital. However, some patients affected by COVID-19 who fully met the criteria for discontinuation of quarantine had another positive real-time reverse transcriptase-polymerase chain reaction (RT-PCR) result at a follow-up visit(An et al., 2020; F. Hu et al., 2020; Lan et al., 2020; Mei et al., 2020; Su et al., 2020; Zheng et al., 2020), which increases the complexity of disease control and has attracted widespread concern.
Several studies, mainly case reports, have been performed to investigate the clinical characteristics and virologic course of discharged patients(An et al., 2020; F. Hu et al., 2020; Lan et al., 2020; Mei et al., 2020; Su et al., 2020; Zheng et al., 2020). However, to date, many questions about patients who tested positive for SARS-CoV-2 again (hereafter, positive retest patients) have not been answered; these questions include the overall prognosis of patients with COVID-19 after meeting the criteria for hospital discharge, the potential risk factors associated with redetectable positive test results, and whether the persistent presence of virus fragments means that the discharged patient is still contagious. As the number of discharged patients increases, effective management becomes critical to successfully reducing the spread of SARS-CoV-2. To promote the comprehensive rehabilitation of COVID-19 patients, China has implemented a series of measures for discharged COVID-19 patients, including management of quarantine, regular follow-up, health monitoring, and rehabilitation therapy, which provide empirical information and evidence support for the management of patients with COVID-19(National_Health_Commission_of_China, 2020).
In this retrospective cohort study, we examined the potential risk factors associated with redetectable positive test results among 745 patients affected by COVID-19 after meeting the criteria for hospital discharge in Guangzhou, China.