The whole-virion inactivated SARS-CoV-2 vaccine, BBV152, was safe and enhanced immune responses, according to a double-blind, multicenter, randomized controlled phase 1 trial published in Lancet Infectious Diseases.
The BBV152 vaccine, produced by Bharat Biotech International, was a whole-virion b-propiolactone-inactivated SARS-CoV-2 vaccine formulated by Algel-alum or Algel-IMDG adjuvants.
Adults (aged 18-55 years; N=375) were recruited at 11 hospitals across India and were randomly assigned to receive 3 mg Algel-IMDG (n=100), 6 mg Algel-IMDG (n=100), 6 mg Algel (n=100) formulations, or an Algel-only placebo (n=75). The vaccine was administered intramuscularly in 2 doses 14 days apart and participants were assessed on days 7, 28, 42, 104, and 194.
Local adverse events after the first dose were reported by 5% of participants in the 3 mg Algel-IMDG and 6 mg Algel-IMDG groups, 1% of participants in the Algel group, and 3% of the placebo recipients. The more frequently reported adverse events were injection site pain (5%), headache (3%), fatigue (3%), fever (2%), and nausea (2%).
Following the second dose, local and systemic reactions occurred among 17% of participants (95% CI, 10.5-26.1%) in the 3 mg Algel-IMDG group, 21% of participants (95% CI, 13.8-30.5%) in the 6 mg Algel-IMDG group, 14% of participants (95% CI, 8.1-22.7%) in the Algel group, and 10% of participants (95% CI, 6.9-23.6%) in the placebo group. No adverse event was severe.
A recipient of the 6 mg Algel BBV152 vaccine developed symptomatic SARS-CoV-2 5 days after receiving the first dose. No other SAS-CoV-2 infections were observed through day 75.
Immunoglobulin (Ig)G titers of spike, nucleocapsid protein, and receptor-binding domain were increased among vaccine recipients. After the second dose, average isotypic ratios (IgG1/IgG4) were greater than 1 for all vaccinated individual, regardless of formulation.
Mean 50% neutralizing titer (NT50) was 87.9% (95% CI, 79.8-94.3%) among the 3 mg Algel-IMDG, 91.9% (95% CI, 84.6-96.0%) among the 6 mg Algel-IMDG, 82.8% (95% CI, 73.7-89.2%) among the Algel, and 8% (95% CI, 3.6-17.2%) among the placebo recipients after both doses.
A subset of individuals were assessed for CD3+, CD4+, and CD8+ T-cell responses. The recipients of the Algel-IMDG formulation exhibited T-cell response but the Algel formulation recipients did not.
This study was likely limited by its low ethnic diversity and bias of including mostly men of relatively young ages. It remains unclear whether a more diverse or older population would exhibit similar vaccine response.
These findings suggested the BBV152 SARS-CoV-2 vaccine from either formulation caused an immune response similar to what has been observed in convalescent plasma with a low risk for severe adverse events.
Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.
Ella R, Vadrevu K M, Jogdand H, et al. Safety and immunogenicity of an inactivated SARS-CoV-2 vaccine, BBV152: a double-blind, randomised, phase 1 trial. Lancet Infect Dis. 2021;S1473-3099(20)30942-7. doi:10.1016/S1473-3099(20)30942-7.