Phase I clinical trial outcome shows Covaxin generates antibody, T-cell memory response

Bharat Biotech’s COVID-19 vaccine  Covaxin has shown positive long term antibody and T cell memory response in Phase I clinical trial.

Covaxin (BBV152) has showed long-term antibody and T-cell memory responses three months after the vaccination in phase I clinical volunteers. The published research report it also indicated that the tolerable safety outcomes with enhanced humoral and cell-mediated immune responses in the Phase II study.

As part of the clinical trial double-blind, randomised, multicentre, phase II clinical trial carried out to evaluate the immunogenicity and safety of BBV152. A total of 380 healthy children and adults were randomised to receive two vaccine formulations (n=190 each) with 3 µg with Algel-IMDG and 6 µwith Algel-IMDG.

According to the paper uploaded on ‘medRxiv’,   two intramuscular doses of vaccines were administered (four weeks apart). Paicipants, investigators, and laboratory staff were blinded to the treatment allocation. The primary outcome was seroconversion (≥4-fold above baseline) based on wild-type virus neutralisation (PRNT50). Secondary outcomes were reactogenicity and safety.

In a follow-up of the phase  I trial, BBV152 produced high levels of neutralising antibodies that remained elevated in all participants three months (at day 104) after the second vaccination. Based on these results, we hypothesize that BBV152 can generate antibodies that may persist for 6-12 months.

Higher neutralising titres (2-fold) was observed in the phase II study than in the phase I study.

Both vaccine groups elicited more Th1-biased cytokines than Th2-biased cytokines.

After two doses, local and systemic adverse reactions observed in both vaccine groups were minimal, and the majority of them resolved within 24 hours of onset.

The findings of research shows no serious adverse events were reported in this study.

The study information is a preprint publish and has not yet undergone peer review. The findings are provisional, and the conclusions/final results may differ. Phase I and II‏ trials are being evaluated by medical peer reviewed journals.