Antibody Response to SARS-CoV-2 in Relation to the Contributing Factors in COVID-19 Patients

Human health has always been challenged by variety of viral infections, but severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has surpassed all previous viral diseases and emerged as a major health challenge around the globe. Real-time polymerase chain reaction (PCR) is the gold standard for the diagnosis of SARS-CoV-2 and serological assay provides a compliment to diagnosis after second week of infection. The aim of the study is the characterization of antibody response to SARS-CoV-2 in the blood sample of diagnosed coronavirus disease 2019 (COVID-19) patients, and its potential association with factors such as age, gender, time, and symptoms. Serum from 248 confirmed SARS-CoV-2 patients was investigated for antibodies. Elecsys anti-SARS chemiluminescent immune assay was performed for the detection of nucleocapsid-specific antibodies. Association of antibody response with gender, age, and time after onset of symptoms was analyzed. Among 248 PCR positive SARS-CoV-2 patients, 214 (86.3%) have virus-specific antibody signals. Antibodies positivity rate was higher in male patient patients as compared with female patients (90.8% vs. 79.2%, p = 0.009). Patients aged 30-40 years had the highest antibody positivity rate as compared with other groups (89.10%, p = 0.04). Patients age group >60 years had a lower positivity rate (75%, p = 0.04). The increasing trend in the antibodies detection with time was observed, maximum positive antibodies response rate observed at 8 weeks. Patients were categorized on the basis of clinical symptoms into asymptomatic, mild, and moderate; 17.7% were asymptomatic, 60.5% showed mild symptoms, and 21.8% showed moderate symptoms of the disease. Males were seen to be more asymptomatic as compared with females (i.e., 59.1% to 40.9%). The serological test for SARS-CoV-2 has a high sensitivity at >2 weeks after the positive PCR result or onset of illness. In addition, the serological response differs among patients based on gender, age, as well as time between the onset of symptoms or PCR confirmation and sample collection for the study of antibody response.