Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 23 2 2024 04 07 158 167 Mahshid Movahedi Division of Allergy and Clinical Immunology, Pediatrics Center of Excellence, Children’s Medical Center Hospital, Tehran University of Medical Sciences, Tehran, Iran Masoud Movahedi Division of Allergy and Clinical Immunology, Pediatrics Center of Excellence, Children’s Medical Center Hospital, Tehran University of Medical Sciences, Tehran, Iran Nima Parvaneh Division of Allergy and Clinical Immunology, Pediatrics Center of Excellence, Children’s Medical Center Hospital, Tehran University of Medical Sciences, Tehran, Iran Hassan Abolhassani Research Center for Primary Immunodeficiencies, Pediatrics Center of Excellence, Children’s Medical Center Hospital, Tehran University of Medical Sciences, Tehran, Iran. AND Division of Immunology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden Mohadese Mahdavi Division of Allergy and Clinical Immunology, Pediatrics Center of Excellence, Children’s Medical Center Hospital, Tehran University of Medical Sciences, Tehran, Iran Mohadese Mosavikhorshidi Division of Allergy and Clinical Immunology, Pediatrics Center of Excellence, Children’s Medical Center Hospital, Tehran University of Medical Sciences, Tehran, Iran Fatemeh Alizadeh Division of Allergy and Clinical Immunology, Pediatrics Center of Excellence, Children’s Medical Center Hospital, Tehran University of Medical Sciences, Tehran, Iran Mehdi Shokri Department of Pediatrics, Faculty of Medicine, Ilam University of Medical Sciences, Ilam, Iran Arash Kalantari Department of Immunology and Allergy, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran 2023 11 26 2024 01 30 Patients with inborn errors of immunity (IEI) are among the high-risk groups regarding COVID-19. Receiving booster doses (third and fourth) in addition to the standard doses is recommended in these patients. This study investigated the antibody response before and after a booster dose of Sinopharm vaccine in IEI patients.  Thirty patients (>12 years) with antibody deficiencies, referred to Imam Khomeini Hospital and Children's Medical Center in Tehran, were enrolled in this prospective cross-sectional study. All patients were fully vaccinated with the BBIBP-CorV vaccine (2 doses of Sinopharm). Initial measurements of anti-receptor-binding domain (anti-RBD) and anti-nucleocapsid (anti-N) IgG antibody responses were conducted by enzyme-linked immunosorbent assay (ELISA). Subsequently, all patients received a booster dose of the vaccine. Four to six weeks after booster injection, the levels of antibodies were re-evaluated.  Twenty patients with common variable immunodeficiency (CVID), 7 cases with agammaglobulinemia and 3 patients with hyper IgM syndrome were studied. Anti-RBD IgG and anti-N IgG antibodies increased in all patients after the booster. Our results indicated the need of receiving booster doses of the COVID-19 vaccine in patients with antibody deficiencies, even for enhancing humoral immune response specially in patients with CVID. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/3959 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/3959/2053