Evaluation of IgG Antibody Response to Severe Acute Respiratory Syndrome Coronavirus-2 in Healthcare Workers in a Tertiary Care Centre, Chennai, India
Published: June 1, 2021 | DOI: https://doi.org/10.7860/JCDR/2021/48889.14995
Therese Mary Dhason, Suganthi Mani Kesi, Usha Krishnan, Vasanthamani, Hema latATha, C Devi, NishatAT, B Manjula
1. Associate Professor, Department of Microbiology, Government Kilpauk Medical College, Chennai, Tamil Nadu, India.
2. Associate Professor, Department of Microbiology, Government Kilpauk Medical College, Chennai, Tamil Nadu, India.
3. Associate Professor, Department of Microbiology, Government Kilpauk Medical College, Chennai, Tamil Nadu, India.
4. Dean, Department of Obstetrics and Gynaecology, Government Kilpauk Medical College, Chennai, Tamil Nadu, India.
5. Assistant Professor, Department of Microbiology, Government Kilpauk Medical College, Chennai, Tamil Nadu, India.
6. Assistant Professor, Department of Microbiology, Government Kilpauk Medical College, Chennai, Tamil Nadu, India.
7. Tutor, Department of Microbiology, Government Kilpauk Medical College, Chennai, Tamil Nadu, India.
8. Medical Laboratory Technician, Department of Microbiology, Government Kilpauk Medical College, Chennai, Tamil Nadu, India.
Correspondence
Dr. Therese Mary Dhason,
Associate Professor, Department of Microbiology, Government Kilpauk Medical College, Kilpauk, Chennai-60010, Tamil Nadu, India.
E-mail: tmary1964@gmail.com
Introduction: Globally, the Coronavirus Disease-2019 (COVID19) pandemic poses a high risk for Healthcare Workers (HCWs) who are among the population that is most vulnerable of being infected with Severe Acute Respiratory SyndromeCoronavirus-2 (SARS-CoV-2). With a prevailing pandemic such as COVID-19, it becomes important to understand the presence and persistence of antibodies in the serum of HCW, testing positive for COVID-19 on Reverse transcriptase Polymerase Chain Reaction (RT-PCR). An understanding of the prevalence of IgG antibodies against COVID-19 and the duration for which they are present in the serum will help in predicting the immune response of individuals against the disease.
Aim: To study the prevalence of COVID-19 IgG antibodies in laboratory confirmed COVID-19 RT-PCR positive symptomatic, asymptomatic and RT-PCR negative subjects.
Materials and Methods: The present longitudinal study was conducted from April to December 2020 with a sample size of 90 participants based on a pilot study. Blood sample was collected and serum was separated. Enzyme Linked Immunosorbent Assay (ELISA) was done to detect the presence of COVID-19 IgG antibody in serum. Chi-square test and Pearson correlation were used to find out the statistical significance of COVID19 IgG antibodies in COVID-19 positive and negative HCWs and the relationship between Cycle threshold values (Ct) and antibody levels, respectively.
Results: Fever with sore throat was the most common (33%) symptom. Chi-square test done to compare IgG among RTPCR positive and negative subjects showed p-value of <0.0001 which was significant. However, statistical significance was not found (p-value 0.9973) with respect to COVID-19 IgG antibodies in RT-PCR positive COVID-19 asymptomatic and symptomatic subjects. Mean antibody index in symptomatic and asymptomatic was 3.7743±1.9834 and 3.571±1.7961, respectively. Average number of days, the antibodies persisted was 25 days-266 days.
Conclusion: The prevalence of COVID-19 antibodies among RTPCR positive symptomatic, asymptomatic and RT-PCR negative subjects was 87.8%, 66.7% and 26.7%, respectively. The maximum number of days antibodies persisted was 266 days. Further studie will elucidate whether these antibodies prevent re-infection.
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