Author/Authors :
Zamani, Mohammad Digestive Diseases Research Institute - Shariati Hospital - Tehran University of Medical Sciences, Tehran, Iran , Ghasemi, Ahmad Healthy Ageing Research Centre - Neyshabur Faculty of Medical Sciences - Neyshabur University Medical Sciences, Neyshabur, Iran , Shamshirgaran, Morteza Healthy Ageing Research Centre - Neyshabur Faculty of Medical Sciences - Neyshabur University Medical Sciences, Neyshabur, Iran , Ahmadpour, Sajjad Gastroenterology and Hepatology Diseases Research Center - Qom University of Medical Sciences, Qom, Iran , Hormati, Ahmad Department of Internal Medicine - Gastroenterology and Hepatology - School of Medicine - Gastrointestinal and Liver Diseases Research Center - Iran University of Medical Sciences, Tehran, Iran , Khodadadi, Javad Infectious Disease Department - Qom University of Medical Sciences, Qom, Iran , Varnasseri, Mehran Infectious and Tropical Diseases Research Center - Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran , Amini, Fatemeh Department of Persian Medicine - School of Medicine - Shiraz University of Medical Sciences, Shiraz, Iran , Shayanrad, Amaneh Liver and Pancreatobiliary Diseases Research Center - Digestive Diseases Research Institute - Shariati Hospital - Tehran University of Medical Sciences, Tehran, Iran , Younesi, Vahid Synapse IVD Accelerator, Tehran, Iran , Poustchi, Hossein Liver and Pancreatobiliary Diseases Research Center - Digestive Diseases Research Institute - Shariati Hospital - Tehran University of Medical Sciences, Tehran, Iran , Shabani, Mahdi Department of Immunology - School of Medicine - Shahid Beheshti University of Medical Sciences, Tehran, Iran
Abstract :
Background: Evidence on seroconversion profile of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected patients is limited. We mainly aimed to evaluate seroconversion and persistence of virus-specific antibodies in patients in-fected by coronavirus disease 2019 (COVID-19).
Methods: This prospective study was conducted on 118 patients with COVID-19 presen-tations admitted to three hospitals in Iran and recovered from the disease, during April and May 2020. Presence of COVID-19 was confirmed by Polymerase Chain Re-action (PCR) testing on nasopharyngeal swabs. Serum samples were collected at dif-ferent time points, including 0-5, 6-15, 16-25, 26-35, and 36-95 days of clinical symp-tom onset. For measurement of SARS-CoV-2-specific IgG and IgM antibody titers, Iran's Food and Drug Administration-approved SARS-CoV-2 ELISA kits were used.
Results: Serologic assay revealed that 37.3% of patients (n=44) were positive for IgM at 0-5 days interval after clinical symptom onset. This rate was 60.2% (n=71) for IgG. There were increasing IgM and IgG seroconversion rates during first 25 days of clinical symptom onset, but seropositivity started to decrease thereafter, which was more evi-dent for IgM (17.9%) than IgG (58.9%) at the 36-95 days post symptoms appearance. In other words, it was found that 83.6% of IgM-positive and 32.9% of IgG-positive pa-tients in the first month of clinical symptom onset became seronegative in the third month of clinical symptom onset.
Conclusion: The findings demonstrated that antibody responses to SARS-CoV-2 infec-tion were developed in recovered COVID-19 patients; however, some of them were seronegative three months after onset of relevant symptoms. Furthermore, the stabil-ity of anti-SARS-CoV-2 antibodies could also correct our expectations from COVID-19 vaccination responses.
