Abstract
Introduction: “Re-infection” with COVID-19 is a growing concern; re-infection cases have reported worldwide. However, the clinical characteristics of SARS-CoV-2 re-infection, including the levels and role of anti-SARS-CoV-2 Spike protein IgG antibodies and the half-maximal concentration (IC 50 ) of neutralizing antibodies remain unknown.
Methods: Both the epidemiological and clinical information has been collected during two episodes of COVID-19 in a patient. Laboratory results, including RT-PCR, Ct values, anti-SARS-CoV-2 Spike protein IgG antibodies, and the IC 50 of neutralizing antibodies levels were analyzed on the patient.
Results: The patient was a 58-year-old man who developed moderate COVID-19 pneumonia with oxygen demand (cannula 2 L/min) in the first episode. By day 30, he recuperated and was discharged after testing negative for SARS-CoV-2. After two and a half months, his three family members showed COVID-19 symptoms and tested positive for SARS-CoV-2. He tested positive for SARS-CoV-2 once again and was asymptomatic (the second episode). The IC 50 of neutralizing antibodies against SARS-CoV-2 greatly increased from 50.0 μg/mL (after the first episode) to 14.8 μg/mL (after the second episode), and remained strongly reactive (20.1 μl/mL) after 47 days of the second episode.
Conclusions: Epidemiological, clinical, and serological analyses confirmed that the patient had re-infection instead of persistent viral shedding from first infection. Our results suggest that SARS-CoV-2 re-infection may manifest as asymptomatic with increased neutralizing antibody levels. Further studies such as the virus characteristics, immunology, and epidemiology on SARS-CoV-2 re-infection are needed.
Keywords: Anti-Spike protein IgG antibody; COVID-19; Neutralizing antibody; Re-infection; SARS-CoV-2.
【저자키워드】 COVID-19, neutralizing antibody, SARS-CoV-2, Re-infection, Anti-Spike protein IgG antibody, 【초록키워드】 immunology, SARS-CoV-2, IgG, Clinical characteristics, Pneumonia, spike, Epidemiology, Infection, viral shedding, oxygen, RT-PCR, virus, anti-SARS-CoV-2, Moderate COVID-19, Protein, IgG antibody, Characteristics, Asymptomatic, IgG antibodies, Patient, epidemiological, serological, Concentration, Analysis, COVID-19 symptom, clinical information, positive, reactive, tested, analyzed, collected, reported, the patient, remained, discharged, with COVID-19, 【제목키워드】 male, Japanese, half-maximal inhibitory concentration, elevated,