Study of neutralizing [anti-RBD] antibody responses induced by COVID-19 vaccines in healthcare professionals in a diagnostic centre of Central India

India began administration of COVID-19 vaccines on 16 January 2021. Reliable quantification of the antibody response to SARS-CoV-2 vaccination is highly relevant for identifying possible vaccine efficiency and estimating the time of protection. Healthcare Professionals were the first group of beneficiaries of this vaccine.we aimed to evaluate the neutralizing [anti-RBD] antibody responses induced by COVID-19 vaccines after first and booster dose in healthcare professionals69 healthcare professionals [HCPs] Were enrolled for the evaluation study. The COVISHILED vaccine developed by AstraZeneca, University of Oxford and manufactured and distributed in India by the Serum Institute of India was administered to all the participants. All participants were evaluated to detect levels neutralizing IgG antibodies on three occasions:,first pre vaccination level, second on approximately 27th day and third on 68th day from baselining & first vaccine dose to assess change in levels of neutralizing IgG antibodies post vaccinationOn approximately 27 day from first vaccine dose, 45 out of 51 participants in investigational cohort were sero-converted for anti-RBD antibodies. Out of 6 participants that were yet to sero-convert 5 demonstrated increased level of neutralizing [anti-RBD] antibodies but did not cross the reactivity threshold to confirm presence of neutralizing [anti-RBD] antibodies.On approximately 68 day from second vaccine dose, 49 out of 51 participants in investigational cohort were sero-converted for anti-RBD antibodies. 4 additional participants sero-converted post booster dose .96.0% produced neutralizing [anti-RBD] antibodies post vaccination. 2 participants continued to remain non-reactive.This is the first data of serological responses to COVID-19 vaccines in IBD patients with detailed analysis of antibodies RBD/spike proteins represented amongst HCPs from central India. Study also demonstrates that the level of neutralizing antibodies produced may vary due to several contributing factors and hence periodic monitoring of neutralizing antibodies before and post vaccination can help evaluate adaptive immune response induced by specific individual in response to vaccine administered.