Antibody and viral RNA kinetics in SARS-CoV2 infected patients admitted to a Romanian University Hospital of Infectious Diseases

Objectives To assess the antibody and viral kinetics in asymptomatic/mild confirmed SARS-CoV-2 infections compared to more severe patients. Material and methods Retrospective analysis of data obtained from adult patients with a confirmed SARS-CoV2 infection having at least one SARS-CoV-2 pair of specific IgM/IgG tests, admitted in The University Hospital of Infectious Diseases Cluj-Napoca, Romania (28 February to 31 August 2020). The database also included: demographic, clinical, chest X-ray and/or CT scan results, RT-PCR SARS-CoV-2, and dexamethasone treatment. A total of 469 patients were evaluated as “asymptomatic/mild” and “moderate/severe/critical” cases. Results The median time since confirmation to SARS-CoV-2 PCR negativity was 15 days [95% CI: 13–18] in asymptomatic/mild cases and 17 days [95% CI: 16–21] in moderate/severe ones. The median time to seroconversion for both IgM and IgG was 13 days [95% CI: 13–14] in asymptomatic/mild cases and 11 days [95% CI: 10–13] in moderate/severe ones. For both antibody types, the highest reactivity was significantly associated with more severe presentation (IgM: OR = 10.30, IgG: OR = 7.97). Conclusion Asymptomatic/mild COVID-19 cases had a faster RT-PCR negativity rate compared to moderate/severe/critical patients. IgG and IgM dynamics were almost simultaneous, more robust for IgG in more severe cases, and at one month after confirmation, almost all patients had detectable antibody titers.