Objective Asymptomatic infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and test re-positivity after a negative test have raised concerns about the ability to effectively control the coronavirus disease 2019 (COVID-19) pandemic. We aimed to investigate the prevalence of COVID-19 asymptomatic and pre-symptomatic infections during the second wave of COVID-19 in Viet Nam, and to better understand the duration of SARS-CoV-2 infection and the dynamics between the evolution of clinical symptoms and SARS-CoV-2 test positivity among confirmed COVID-19 cases. Methods We conducted a cohort analysis on the first 50 confirmed cases during the second COVID-19 wave in Viet Nam using clinical, laboratory and epidemiological data collected from 9 March to 30 April 2020. Kaplan–Meier estimates were used to assess time to clearance of SARS-CoV-2 infection, and log-rank tests were used to explore factors related to time to SARS-CoV-2 infection clearance. Results Most cases (58%) had no typical signs or symptoms of COVID-19 at the time of diagnosis. Ten cases (20%) were re-positive for SARS-CoV-2 during infection. Eight cases (16%) experienced COVID-19 symptoms after testing negative for SARS-CoV-2. The median duration from symptom onset until clearance of infection was 14 days (range: 6–31); it was longer in re-positive and older patients and those with pre-existing conditions. Conclusion Asymptomatic and pre-symptomatic infections were common during the second wave of COVID-19 in Viet Nam. Re-positivity was frequent during hospitalization and led to a long duration of SARS-CoV-2 infection.
【초록키워드】 COVID-19, coronavirus disease, Evolution, SARS-CoV-2, coronavirus, pandemic, Hospitalization, SARS-COV-2 infection, Infection, Diagnosis, Laboratory, older patient, Asymptomatic, pre-symptomatic, second wave, epidemiological data, estimate, COVID-19 cases, COVID-19 symptom, confirmed case, symptom onset, acute respiratory syndrome, Factor, clinical symptom, log-rank test, symptoms of COVID-19, SARS-CoV-2 test, clearance, MOST, cohort analysis, negative test, Kaplan–Meier, objective, Result, collected, raised, conducted, median, were used, had no, conditions, clearance of SARS-CoV-2, prevalence of COVID-19, 【제목키워드】 Isolation, COVID-19 case, clinical evolution, clearance,