Background: The coronavirus disease (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a major global public health issue. SARS-CoV-2 infection is confirmed by the detection of viral RNA using reverse transcription polymerase chain reaction (RT-PCR). Prolonged viral shedding has been reported in patients with SARS-CoV-2 infection, but the presence of viral RNA does not always correlate with infectivity. Therefore, the present study aimed to confirm the presence of viable virus in asymptomatic or mildly symptomatic patients in the later phase of the disease, more than two weeks after diagnosis. Method: Asymptomatic or mildly symptomatic COVID-19 patients who had been diagnosed with the disease at least two weeks previously and admitted to a community treatment center (CTC) from 15 March to 10 April 2020 were enrolled in this study. Nasopharyngeal and salivary swab specimens were collected from each patient. Using these specimens, RT-PCR assay and viral culture were performed. Result: In total, 48 patients were enrolled in this study. There were no significant differences in baseline characteristics between the asymptomatic and mildly symptomatic patient groups. RT-PCR assay and viral culture of SARS-CoV-2 were performed using nasopharyngeal and salivary swabs. The results of RT-PCR performed using salivary swab specimens, in terms of cycle threshold (Ct) values, were similar to those of RT-PCR using nasopharyngeal swab specimens. In addition, no viable virus could be cultured from swab specimens collected from the late-phase COVID-19 patients with prolonged viral RNA shedding. Conclusions: In conclusion, our study suggests that even if viral shedding is sustained in asymptomatic or mildly symptomatic patients with later phase of COVID-19, it can be expected that the transmission risk of the virus is low. In addition, saliva can be used as a reliable specimen for the diagnosis of SARS-CoV-2 infection.

(1) Background: Lung transplant recipients (LTRs) are at substantial risk of invasive fungal disease (IFD), although no consensus has been reached on the use of antifungal agents (AFAs) after lung transplantation (LTx). This study aimed to assess the risk factors and prognosis of fungal infection after LTx in a single tertiary center in South Korea. (2) Methods: The study population included all patients who underwent LTx between January 2012 and July 2019 at a tertiary hospital. It was a retrospective cohort study. Culture, bronchoscopy, and laboratory findings were reviewed during episodes of infection. (3) Results: Fungus-positive respiratory samples were predominant in the first 90 days and the overall cumulative incidence of Candida spp. was approximately three times higher than that of Aspergillus spp. In the setting of itraconazole administration for 6 months post-LTx, C. glabrata accounted for 36.5% of all Candida-positive respiratory samples. Underlying connective tissue disease-associated interstitial lung disease, use of AFAs before LTx, a longer length of hospital stay after LTx, and old age were associated with developing a fungal infection after LTx. IFD and fungal infection treatment failure significantly increased overall mortality. Host factors, antifungal drug resistance, and misdiagnosis of non-Aspergillus molds could attribute to the breakthrough fungal infections. (4) Conclusions: Careful bronchoscopy, prompt fungus culture, and appropriate use of antifungal therapies are recommended during the first year after LTx.