PROSPECTIVE FOLLOW-UP AND RESULTS OF NEUTRALIZING ANTIBODY LEVELS OF PATIENTS DURING THE PANDEMIC PERIOD

ABSTRACT
Objective: The COVID-19 pandemic has affected the entire world. Understanding the humoral immune response is crucial for protection against the disease, prevention of reinfections and guiding vaccine development.
Materials and Methods: A hundred patients who were over 18 years of age, did not have pregnancy or additional immunosuppressive diseases and had a positive SARS-CoV-2 PCR test were included in the study. Blood samples were taken from the patients on the 7th day, 15th day, in the 1st month, 3rd month and 6th month and COVID-19 IgM and IgG antibody levels were recorded both as positive or negative and quantitatively. 
Results: The COVID-19 IgM and IgG antibodies of the patients were found positive at the following rates: 65% and 94% in the 3rd month, and 35% and 100% in the 6th month, respectively. Higher antibody levels were observed in patients with symptoms such as fatigue, cough and shortness of breath, those with lung involvement in chest tomography. Positive correlations were found between lymphocyte count, C-reactive protein, procalcitonin levels and antibody levels.
Conclusion: Our findings indicated the presence of a significant level of neutralizing antibodies which persisted for 6 months in patients who recovered from COVID-19. These results contribute to understanding the immunological response to COVID-19, and may have implications for long-term immunity and vaccine strategies.
Keywords: Antibody level, COVID-19, Neutralizing antibody