SARS-COV-2 IgG specific antibodies persistence in recovered COVID-19 individuals and its association with severity and time of illness.

In order to accurately interpret the immune response to COVID-19, it is critical to know how long serum antibodies to COVID-2 persist. This study aimed to describe the serum IgG responses to SARS-CoV-2 in patients with mild, moderate, and severe COVID-19 infection in Birjand, South Khorasan province, Iran. The study was performed on individuals whose COVID-19 disease was confirmed by RT-PCR and recovered from the disease. After completing the questionnaire, blood samples were collected from 4 different groups based on the time of the test at two, four, six, and eight months' post-recovery. Then, SARS-COV-2 virus-specific IgG nucleocapsid antibody level in patients was measured using the enzyme-linked immunosorbent assay (ELISA). In total, 206 patients (mean age 44.19 ± 14.9, 51% man) were included in the survey. Serum prevalence of specific IgG antibodies in patients with mild, moderate, and severe COVID-19 disease was 51.5%, 64% and 78.9%, respectively. Furthermore, serum prevalence of COVID-19 specific IgG antibody level in two, four, six, and eight months after recovery were 80.8, 69.1, 43.2 and 41.8%, respectively (p < 0.05). The multiple logistic regression model showed that the variables of age and the time elapsed after recovery had a significant relationship with the positive antibody test of recovered COVID-19 patients (P < 0.05). But other variables had no significant relationship with the result of antibody test (P > 0.05). In the present report, we attempted to characterize the antibody response against SARS-CoV-2 in patients with mild, moderate, and severe COVID-19, with the aim of better elucidating the humoral immune response after recovery from SARS-CoV-2 infection.

Seroprevalence of SARS-COV-2 antibodies among health-care workers exposed to COVID-19 patients in a large reference hospital, Iran.

Background and Objectives: Health care workers (HCWs) are a high-risk group for acquiring and transmitting severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Aim of the study was the evaluation of seroprevalence of SARS-CoV-2 in a random sample of HCWs at a large acute care hospital in Iran. Materials and Methods: We collected blood samples of 180 medical staffs from September 22, 2020 to January 26, 2021. The enzyme linked immunosorbent assays (ELISA) tests were used for evaluation of the presence of IgG antibodies. Participants completed a self-report questionnaire, comprising demographics, occupational, the work area, and personal protection data. Results: Of the 180 HCWs who participated in this study, 44 (24.4%) were seropositive for anti-SARS-CoV-2 IgG. The percentage of IgG positivity was higher in males than females (P<0.05). Also, there was statistically significant difference between presence of the antibodies and the occupation, location, and infecting family members with Covid -1 (P<0.05). Other factors did not associate significantly to antibody presence against SARS-CoV-2 (P>0.05). Conclusion: According to this point that the number of COVID-19 cases is still growing rapidly among HCWs. So, the epidemiological estimate of SARS-CoV-2 infection remains a major challenge that is needed to prevent the spread of infection in the hospitals.