Background Early and accurate detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical to prevent spread of the infection. Understanding of the antibody response to SARS-CoV-2 in patients with coronavirus disease 2019 (COVID-19) is insufficient, particularly in relation to those whose responses persist for more than 1 month after the onset of symptoms. We conducted a SARS-CoV-2 antibody test to identify factors affecting the serological response and to evaluate its diagnostic utility in patients with COVID-19. Methods and finding We collected 1,048 residual serum samples from 396 patients with COVID-19 confirmed by real-time reverse transcription polymerase chain reaction (RT-PCR) for SARS-CoV-2. The samples had been used for routine admission tests in six healthcare institutions in Daegu. Antibody to SARS-CoV-2 was analyzed and the cutoff index (COI) was calculated for quantitative analysis. The patients’ information was reviewed to evaluate the relationship between antibody positivity and clinical characteristics. The anti-SARS-CoV-2 antibody positivity rate was 85% and the average COI was 24·3. The positivity rate and COI increased with time elapsed since symptom onset. Anti-SARS-CoV-2 antibody persisted for at least 13 weeks after symptom onset at a high COI. There was a significant difference in anti-SARS-CoV-2 antibody positivity rate between patients with and without symptoms, but not according to sex or disease course. The descending COI pattern at weeks 1 to 5 after symptom onset was significantly more frequent in patients who died than in those who recovered. Conclusions Anti-SARS-CoV-2 antibody persisted for at least 13 weeks at a high COI in patients with COVID-19. A decreasing COI pattern up to fifth week may be associated with a poor prognosis of COVID-19. As new treatments and vaccines are introduced, it is important to monitor continuously the usefulness of anti-SARS-CoV-2 antibody assays.
【초록키워드】 COVID-19, Treatment, coronavirus disease, SARS-CoV-2, Coronavirus disease 2019, Vaccine, coronavirus, Clinical characteristics, antibody, Antibody Response, Infection, diagnostic, Sex, severe acute respiratory syndrome Coronavirus, RT-PCR, Spread, polymerase chain reaction, SARS-CoV-2 antibody test, anti-SARS-CoV-2 antibody, response, healthcare, Patient, understanding, reverse transcription, Antibody test, respiratory, utility, information, Admission, Critical, serological response, Chain Reaction, symptom onset, Real-Time Reverse Transcription Polymerase Chain Reaction, Quantitative analysis, acute respiratory syndrome, Factor, significant difference, acute respiratory syndrome coronavirus, acute respiratory syndrome coronavirus 2, average, disease course, poor prognosis, Cutoff, serum sample, MONITOR, Prevent, polymerase chain, analyzed, identify, collected, evaluate, significantly more, died, assays, conducted, calculated, introduced, onset of symptoms, affecting, the antibody response, descending, elapsed, patients with COVID-19, without symptoms, 【제목키워드】 Patient, South Korea,