Coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although Thailand has been fairly effective at controlling the spread of COVID-19, continued disease surveillance and information on antibody response in recovered patients and their close contacts remain necessary in the absence of approved vaccines and antivirals. Here, we examined 217 recovered COVID-19 patients to assess their viral RNA shedding and residual antibodies against SARS-CoV-2. We also evaluated antibodies in blood samples from 308 close contacts of recovered COVID-19 patients. We found that viral RNA remained detectable in 6.6% of recovered COVID-19 cases and up to 105 days. IgM, IgG, and IgA antibodies against SARS-CoV-2 were detected in 13.8%, 88.5%, and 83.4% of the recovered cases 4–12 weeks after disease onset, respectively. Higher levels of antibodies detected were associated with severe illness patients experienced while hospitalized. Fifteen of the 308 contacts (4.9%) of COVID-19 cases tested positive for IgG antibodies, suggesting probable exposure. Viral clearance and the pattern of antibody responses in infected individuals are both crucial for effectively combating SARS-CoV-2. Our study provides additional information on the natural history of this newly emerging disease related to both natural host defenses and antibody duration.
【초록키워드】 COVID-19, coronavirus disease, SARS-CoV-2, IgG, IgM, Coronavirus disease 2019, Vaccine, coronavirus, Hospitalized, antibody, antivirals, Antibody Response, severe acute respiratory syndrome Coronavirus, viral clearance, Antibody responses, Viral, IgG antibodies, Patient, emerging disease, Disease surveillance, Viral RNA, recovered patients, respiratory, pattern, information, Recovered COVID-19 patients, close contact, Contact, COVID-19 cases, disease onset, natural history, host defenses, acute respiratory syndrome, Viral RNA shedding, acute respiratory syndrome coronavirus, acute respiratory syndrome coronavirus 2, Blood samples, COVID-19 case, infected individual, infected individuals, IgA antibodies, blood sample, positive, Defense, clearance, Host, effective, recovered COVID-19 patient, spread of COVID-19, combating, recovered patient, tested, examined, caused, remained, detectable, evaluated, approved, provide, absence, IgA antibody, levels of antibody, 【제목키워드】 SARS-CoV-2, SARS-CoV-2 RNA, COVID-19 case, presence of antibody,