GOENKA, MAHESH KUMARGOENKA, USHAPATIL, VIKRAM UTTAMDAS, SUDIPTA SEKHARAFZALPURKAR, SHIVARAJJAJODIA, SURABHIMUKHERJEE, MUHUYASHAH, BHAVIK BHARATMOITRA, SAIBAL2023-06-272023-06-272022-08GOENKA MAHESH KUMAR, GOENKA USHA, PATIL VIKRAM UTTAM, DAS SUDIPTA SEKHAR, AFZALPURKAR SHIVARAJ, JAJODIA SURABHI, MUKHERJEE MUHUYA, SHAH BHAVIK BHARAT, MOITRA SAIBAL. Kinetics of Covid-19 antibodies in terms of titre and duration among healthcare workers: A longitudinal study. The National Medical Journal of India. 2022 Aug; 35(4): 201-2050970-258X2583-150Xhttp://imsear.searo.who.int/handle/123456789/218208BACKGROUND Most individuals with Covid-19 infection develop antibodies specific to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the dynamics of these antibodies is variable and not well-studied. We aimed to determine the titres of naturally acquired antibodies over a 12-week follow-up. METHODS We recruited healthcare workers who had tested positive on a specific quantitative reverse transcription-polymerase chain reaction (qRT-PCR) for SARS-CoV-2, and then tested for the presence of immunoglobulin G (IgG) antibody against the same virus at baseline and again at 6 and 12 weeks. The antibody titre was determined by a semi-quantitative assay based on signal/cut-off ratio. Healthcare workers with antibody positivity were divided into those with high titre (ratio ?12) and low titre (<12). Their demographic details and risk factors were surveyed through a Google form and analysed in relation to the antibody titres at three time-points. RESULTS Of the 286 healthcare workers, 10.48% had high antibody titres. Healthcare workers who had tested positive by qRT-PCR and those who had received the Bacille Calmette–Guérin (BCG) vaccination or other immune-boosters had a higher frequency of high antibody titres. While there was a significant decline in antibody titres at 6 and 12 weeks, 87.46% of individuals positive for IgG antibody persisted to have the antibody even at 12 weeks. CONCLUSION Healthcare workers who tested positive for SARS-CoV-2 on qRT-PCR had a high positivity for the specific antibody, which continued to express in them even at 12 weeks. Further follow-up is likely to enhance our understanding of antibody kinetics following SARS-CoV-2 infection.Journal ArticleIndiaDepartment of Clinical Imaging and Interventional Radiology, Apollo Multispeciality Hospitals, Institute of Gastrosciences and Liver, Kolkata, West Bengal, IndiaDepartment of Transfusion Medicine and Blood Bank, Apollo Multispeciality Hospitals, Institute of Gastrosciences and Liver, Kolkata, West Bengal, IndiaDepartment of Biostatistics, Apollo Multispeciality Hospitals, Institute of Gastrosciences and Liver, Kolkata, West Bengal, IndiaDepartment of Allergy and Asthma Research Centre, Apollo Multispeciality Hospitals, Institute of Gastrosciences and Liver, Kolkata, West Bengal, India