This study aimed to monitor severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral loads and specific serum-antibodies (immunoglobulin [Ig] G and M) among confirmed patients and asymptomatic carriers from returning healthy travelers. The throat swabs, sputum, and stool samples from 57 hospitalized coronavirus disease (COVID-19) patients and 8 asymptomatic carriers, among 170 returning healthy travelers were tested using reverse-transcription real-time polymerase chain reaction. SARS-CoV-2 IgM/IgG antibodies were detected via serum chemiluminescence assay. Sequential results showed higher viral RNA loads in the throat, sputum, and stool samples at 3–12 and 6–21 days after symptom onset among severely ill COVID-19 patients. Shorter viral habitation time (1–8 days) was observed in the oropharyngeal site and intestinal tract of asymptomatic carriers. The IgG and IgM response rates were 19/37 (51.4%) and 23/37 (62.6%) among the 29 confirmed patients and 8 asymptomatic carriers, respectively, within 66 days from symptom or detection onset. The median duration between symptom onset and positive IgG and IgM results was 30 (n=23; interquartile range [IQR]=20–66) and 23 (n=19; IQR=12–28) days, respectively. Of 170 returning healthy-travelers to China, 4.7% were asymptomatic carriers (8/170) within 2 weeks, and the IgG and IgM positivity rate was 12.8% (12/94). IgM/IgG-positivity confirmed 3 suspected SARS-CoV-2 cases, despite negative results for SARS-CoV-2 RNA. Compared with other respiratory viral infectious diseases, COVID-19 has fewer asymptomatic carriers, lower antibody response rates, and a longer antibody production duration in recovered patients and the contacted healthy population. This is an indication of the complexity of COVID-19 transmission.
【저자키워드】 coronavirus disease, IgG, IgM, severe acute respiratory syndrome coronavirus-2, Asymptomatic carriers, viral RNA load, 【초록키워드】 COVID-19, coronavirus disease, SARS-CoV-2, coronavirus, Diseases, Hospitalized, antibody, Antibody Response, Asymptomatic carrier, Symptom, severe acute respiratory syndrome Coronavirus, sputum, China, polymerase chain reaction, serum, Stool, Viral, Immunoglobulin, Viral load, IgG antibodies, IgM/IgG, Patient, Asymptomatic carriers, SARS-CoV-2 RNA, Viral RNA, Oropharyngeal, recovered patients, respiratory, chemiluminescence, COVID-19 patients, SARS-CoV-2 IgM, stool samples, COVID-19 transmission, antibody production, IgG and IgM, Chain Reaction, response rates, specific serum, symptom onset, interquartile range, acute respiratory syndrome, acute respiratory syndrome coronavirus 2, throat swabs, indication, complexity, viral loads, severely ill COVID-19 patients, intestinal tract, positive, MONITOR, respiratory viral, polymerase chain, recovered patient, tested, healthy, median, 【제목키워드】 coronavirus, coronavirus 2, RNA, China, Viral, Asymptomatic carriers, respiratory, status, load, carrier,