Immunity among covid 19 survivors

Background: COVID-19 is a global pandemic that affected millions of people all over the world since 2019. Infection with COVID-19 initiates a humoral immune response that produces antibodies against specific viral antigens which in turn is supposed to provide immunity against reinfection for a period of time. The aim of current research is to study the kinetics of IgM and IgG antibodies against SARS-CoV-2. Method: 117 post COVID-19 participants were enrolled in the study. Qualitative assessment of IgM and IgG antibodies over 6 months (3 visits) post recovery was conducted. Results: Current study revealed significant reduction in IgM and IgG titers between 1st and 2nd visits (p< 0.001). By the end of 6 months, antibody titer declined by 78.8% from 1st visit for IgM and by 49.2% for IgG antibodies. Regarding younger age and male gender, statistically significant persistence of IgM antibodies was noticed at the 6 months follow up. Also, statistically significant persistent IgG immunity was found in male patients and diabetics by the end of 6 months follow up. Conclusion: There was significant waning of IgM and IgG titers over a period of 6 months follow up was observed. The persistence of positive IgM and IgG antibodies by the end of 6 months was variable due to differences in age, gender and presence of diabetes mellitus.背景：新型冠状病毒肺炎（COVID-19）自2019年以来已成为影响全球数百万民众的全球性大流行病。感染COVID-19可触发体液免疫应答（humoral immune response），产生针对特定病毒抗原的抗体，进而在一段时间内为机体提供针对再感染的免疫力。本研究旨在探讨针对严重急性呼吸综合征冠状病毒2型（SARS-CoV-2）的免疫球蛋白M（IgM）和免疫球蛋白G（IgG）抗体的动态变化规律。 方法：本研究纳入117名新冠感染后康复参与者，在康复后6个月内（共3次随访）对IgM和IgG抗体进行定性检测。 结果：本研究显示，在第1次与第2次随访期间，IgM与IgG抗体滴度均出现显著下降（p<0.001）。至随访6个月结束时，IgM抗体滴度较第1次随访时下降78.8%，IgG抗体滴度下降49.2%。亚组分析显示，较年轻者与男性群体的IgM抗体在6个月随访时仍具有统计学意义的持续阳性。此外，6个月随访结束时，男性患者与糖尿病患者的IgG抗体免疫水平同样呈现具有统计学意义的持续存在。 结论：本研究观察到，在6个月的随访周期内，IgM与IgG抗体滴度均出现显著衰减。至随访6个月结束时，IgM与IgG抗体阳性的持续状态存在个体差异，该差异与年龄、性别以及是否合并糖尿病（diabetes mellitus）相关。