Comparison of Antibody Status Following COVID-19 Vaccination between SARS-Cov-2 Infected and Non-infected Healthcare Professionals of Bangabandhu Sheikh Mujib Medical University (BSMMU), Bangladesh

Abstract

BACKGROUND Antibody developed through COVID-19 vaccination plays a vital role in combating further infection and suppressing pathogenesis of SARS-CoV-2. This study aims to observe the difference in antibody status between COVID-19 infected and non-infected healthcare professionals following two doses of COVID-19 vaccine.

METHODS This cross-sectional, analytical study was conducted in the Department of Biochemistry and Molecular Biology of Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh, between March 2021 and February 2022. A total of 70 adult participants (healthcare professionals) were included in this study from different departments of BSMMU Hospital. Study participants were categorized into two groups; each group had 35 participants. Group A includes healthcare professionals who were infected by SARS CoV-2 and later vaccinated by two doses of AstraZeneca COVID-19 vaccine, while Group B consists of those who were not infected by SARS CoV-2 but took two doses of AstraZeneca COVID-19 vaccine. We collected participants’ demographic profile and detailed history including co-morbidities and related test results in the data collection sheet. Serum IgG was assessed by chemiluminescent microparticle immunoassay method.

RESULTS Serum IgG levels were found in group A as a median 2183.2 AU/ml with an IQR (inter quartile range) of 3852.0 AU/ml, while in group B, median was 624.7 AU/ml and IQR was 621.1 AU/ml (p<0.001). Moreover, participants having comorbidities also showed differences in IgG levels (group A median 2183.20 AU/ml, and IQR of 4095.70 AU/ml; group B median 624.70 AU/ml and IQR of 558.80 AU/ml) (p<0.001). Similarly, among participants with no comorbidities significant differences in IgG levels were observed (group A median 2394.45 AU/ml, and IQR 3450.73 AU/ml; group B median 653.10 AU/ml, and IQR 990.13 AU/ml) (p<0.001).

CONCLUSION To conclude, antibody status (serum IgG levels) was found significantly higher in previously infected vaccinated group (group A) compared to non-infected vaccinated group (group B).