Detection and Predictors of anti-SARS-CoV-2 Antibody Levels in COVID-19 Patients at 8 Months After Symptom Onset

Abstract

Aim: To determine SARS-CoV-2 specific IgM and IgG levels of patients with COVID-19 at 8 months after symptom onset and to explore the predictors of antibody levels. Materials & methods: The magnetic chemiluminescence method was used to measure the antibody levels. Clinical data were collected and analyzed retrospectively. Results: A total of 54 patients were enrolled in this study, of whom 59.3% were IgM positive and 96.4% were IgG positive. The multiple linear regression analysis revealed that the duration of RNA shedding, C-reactive protein level and disease severity were independent predictors of IgG levels. Conclusion: COVID-19 patients retained long-term viral-specific protective immunity. Disease severity, C-reactive protein level and duration of RNA shedding were related to antibody levels 8 months after symptom onset.

Lay abstract

This study aimed to detect the levels of antibodies made by the body in response to COVID-19, 8 months after infection. We reviewed the characteristics of 54 patients with a history COVID-19 to find factors that may influence antibody levels. The results showed that 8 months after infection, almost all the patients had sufficient antibody levels to protect them from another episode of COVID-19 and that antibody levels were especially well maintained in those with a history of severe COVID-19.

Keywords:

• antibody
• COVID-19
• IgG
• IgM
• SARS-CoV-2

Author contributions

L Li and Q Wu conceptualized the study. J Guo, Q Wu, H Li, Y Li, X Hou, F Yang and Z Qin contributed to the collection and detection of clinical samples. J Guo analyzed the data and wrote the manuscript. All authors reviewed and approved the final version.

Acknowledgments

The authors thank their colleagues in the Department of Respiratory Medicine and Laboratory, Haihe Hospital, Tianjin University, Tianjin, China, for generously helping with the collection of medical records.

Financial & competing interests disclosure

This study was supported by Tianjin Haihe Hospital Science and Technology Fund (HHYY-202001), the Science and Technology Planning Project of Tianjin Jinnan District (20200112), and the National Key R&D Program of China (2019YFC0119405). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

The authors would like to thank Editage (www.editage.com) for providing editing support, which was funded by Tianjin Haihe Hospital Science and Technology Fund (HHYY-202001).

Ethical conduct of research

This study was approved by the Medical Ethics Committee of Haihe Hospital, Tianjin, China (2020HHKT-023) and informed consent was obtained from the participants.

Data sharing statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.