Safety and Immunogenicity Trial of an Inactivated SARS-CoV-2 Vaccine-BBV152: A Phase 1, Double-Blind, Randomised Control Trial

Background: BBV152 is a whole-virion inactivated SARS-CoV-2 vaccine (3 μg or 6 μg) formulated with a Toll-Like Receptor 7/8 agonist molecule adsorbed to alum (Algel-IMDG) or 6 μg with alum (Algel). Methods: We conducted a double-blind, randomised, multicentre, controlled phase 1 clinical trial to evaluate the safety and immunogenicity of BBV152. A total of 375 healthy adults Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation were randomised equally to receive three vaccine formulations (n=100 each) prepared with 3 μg with Algel-IMDG, 6 μg with Algel-IMDG, and 6 μg with Algel, and an Algel only control arm (n=75). Two intramuscular doses of vaccines were administered (twoweeks apart). Primary outcomes were reactogenicity and safety. Secondary outcome was seroconversion (≥4-fold above baseline) based on wild-type virus neutralisation. Cell-mediated responses were evaluated by intracellular staining and ELISpot. Findings: Among 827 participants screened between July 13 and July 30, 2020, 375 participants were randomised. After both doses, the proportion (95%CI) of solicited local and systemic adverse reactions were 17% (10·5, 26·1), 21% (13·8, 30·5), 14% (8·1, 22·7), and 10% (6·9, 23·6) in the 3 μg with Algel-IMDG, 6 μg with Algel-IMDG, 6 μg with Algel, and control groups, respectively . The most common solicited adverse events were injection site pain, headache, and fatigue. All solicited adverse events were mild (43, 69·3%) or moderate (19, 30·7%) and were more frequent after the first dose. One serious adverse event was reported in the 6 μg with Algel group, unrelated to the vaccine. Seroconversion rates (%) were 87·9, 91·9, and 82·8 in the 3 μg with AlgelIMDG, 6 μg with Algel-IMDG and 6 μg with Algel groups, respectively. CD4 + and CD8 + T cell responses were detected in a subset from both Algel-IMDG groups. Interpretations: BBV152 led to tolerable safety outcomes and enhanced immune responses. Both Algel-IMDG formulations were selected for phase 2 immunogenicity trials. Further efficacy trials are warranted. Trial Registration Number: Clinicaltrials.gov : NCT04471519 Funding: This work was supported and funded by Bharat Biotech International Limited. Conflict of Interest: This work was supported and funded by Bharat Biotech International Limited. All authors are employees of one of the above-mentioned organisations, with no stock options or incentives. Co-author- K.E is the Chairman and Managing Director of Bharat Biotech. Ethical Approval: The trial was conducted across 11 sites in 9 states in India. The trial was approved by the National Regulatory Authority (India) and the respective Ethics Committees and was conducted in compliance with all International Council for Harmonization 114 (ICH) Good Clinical Practice guidelines.