Asymptomatic infection and atypical manifestations of COVID-19: Comparison of viral shedding duration
Dear Editor,Coronavirus disease 2019 (COVID-19) bears several challenging problems, including insidious symptom onset, subclinical manifestations and highly transmissible property during early stage of infection. 1 In the recent study by Huang et al., SARS-CoV-2infection presented strong infectivity during the incubation period with rapid transmission. 2 Some patients with COVID-19 are asymptomatic, while others complain of atypical symptoms including loss of smell and taste sense. 3 However, there is insufficient data on the prevalence of asymptomatic infection and atypical manifestations of COVID-19. In this study, we aimed to evaluate the prevalence of asymptomatic infection, anosmia (smell loss) and ageusia (taste loss) among patients with mild COVID-19 in a residential treatment center (RTC). We also compared the duration of SARS-CoV-2 viral shedding between groups with different clinical manifestations.An observational cohort study was conducted for 199 patients with COVID-19 in a RTC at Gyeongju, Gyeongsangbuk province, Republic of Korea (ROK). The RTC was introduced to care patients with mild COVID-19 for the efficient distribution of limited medical resources during large epidemic in early March 2020. Data on demographic findings, symptoms, and duration of viral shedding were collected. The patients were interviewed about initial symptoms and their duration in detail. Real-time PCR (RT-PCR) to detect SARS-CoV-2 was performed every 2-7 days. Duration of viral shedding was considered as time from diagnosis date to the day before first negative conversion of two consecutive negative results of RT-PCR. RT-PCR was conducted using Allplex 2019-nCoV assay (Seegene, Seoul, South Korea). Statistical analyses were performed using SPSS 20.0 program. Mann-Whitney U test was performed to compare the duration of viral shedding between groups with different clinical manifestations. P -value < 0.05 was considered statistically significant. This study was approved by the Institutional Review Board of Korea University Guro Hospital (approval number: 2020GR0135).Among 199 patients with COVID-19, male was 34.7% and mean age of the patients was 38.0 years ( Table 1 ). Most patients (187, 94.0%) were healthy without chronic medical conditions. Among 199 patients, 26.6% were asymptomatic. In the early study, asymptomatic cases accounted for 10.7% (3/28) of COVID-19 cases in the ROK. 1 Asymptomatic proportion of COVID-19 was estimated as 17.9% (95% credible interval, 15.5-20.2%) on the Diamond Princess cruise ship, Japan. 4 Among clinical manifestations, cough (41.2%) was most common, followed by rhinorrhea and nasal stuffiness (30.2%). Of note, 26.1% (52/199) of patients presented anosmia, and 22.6% (45/199) complained of ageusia. Thirty-eight (19.1%) patients complained of both anosmia and ageusia. Duration of anosmia and Duration of viral shedding (days, mean ± SD) p value Asymptomatic 22.6 ± 4.0 < 0.01 * Symptomatic 25.2 ...