The Phase I trials of COVAXIN BBV152 inactivated vaccine prepared against SARS-CoV-2 was conducted between 13th to 30th July 2020. It involved 375 participants, of which 100 each were assigned to three different groups that were administered different vaccine doses. The control group was formed by 75 participants. The trial took place at 11 hospitals across nine states in India and the participants were aged between 18 to 55 years old.
The participants were initially screened for COVID-19 through the gold-standard RT-PCR test. The original pool comprised 827 people but those with a temperature above 37 degrees celsius and a known allergy to any vaccine component were excluded.
The three vaccine formulations administered were “3 µg with Algel-IMDG, 6 µg with Algel-IMDG, or 6 µg with Algel”. Algel-IMDG, or chemosorbed imidazoquinoline onto the aluminum hydroxide gel, is the adjuvant (toll-like receptor (TLR) 7/8 agonist) which is used with the vaccine in order to boost immune response. The vaccine is supposed to induce T-helper-1 cell (Th1) responses. According to the study, adverse events were reported in 17 participants in the first group, 21 in the second group, 14 in the third group and 10 in the control group. There was only one serious adverse event which had been reported in the third group that was administered 6 µg of the vaccine with Algel, a case of viral pneumonitis, which the researchers ascertained was unrelated to the vaccine.
The Lancet study concluded “BBV152 led to tolerable safety outcomes and enhanced immune responses.” Both the Algel-IMDG formulations were selected for Phase II immunogenicity trials.