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

Abstract

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.

Keywords

• SARS-CoV-2
• COVID-19
• Viral kinetics
• antibody profile