‘Well-tolerated, no serious adverse events’ — Lancet publishes Covaxin’s phase 1 trial data

A preprint of the results were released last month, which revealed that all three vaccine formulations in the trial resulted in 'robust immune responses'.

Covaxin is manufactured by the Hyderabad-based Bharat Biotech | ANI Photo

New Delhi: The results of the phase 1 trials of the indigenous Covid-19 vaccine, Covaxin, was published in prominent medical journal The Lancet Thursday.

A preprint of the paper, released last month, had indicated that all three vaccine formulations or dosages had resulted in “robust immune responses comparable to a panel of convalescent serum” in the 375 volunteers across 11 hospitals.

According to The Lancet, “The vaccine was well tolerated in all dose groups with no vaccine-related serious adverse events,”.

It added: “The most common adverse event was pain at the injection site, followed by headache, fatigue, and fever.”

Covaxin has been developed by Bharat Biotech in collaboration with the Indian Council of Medical Research. The vaccine received emergency use authorisation earlier this month, despite incomplete phase 3 trial data, which had sparked a controversy.

The study

The phase 1 trials of Covaxin took place between 13 and 30 July last year. 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, which is used with the vaccine to boost immune response.

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.

Only one serious adverse event 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.

“BBV152 led to tolerable safety outcomes and enhanced immune responses. Both Algel-IMDG formulations were selected for phase 2 immunogenicity trials,” concluded the phase 1 results.