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Coronavirus | Covaxin phase-1 trial results show promising results

A medic fills a syringe with Covaxin, a COVID-19 vaccine, in Ahmedabad. File   | Photo Credit: Reuters

Phase-1 results show that Covaxin, a proposed COVID-19 vaccine, is safe. The results find it to be well-tolerated in all dose groups, and that it generates immune response according to results released in a preprint paper titled ‘A Phase 1: Safety and Immunogenicity Trial of an Inactivated SARS-CoV-2 Vaccine- BBV152’.

The interim findings from the phase-1 placebo-controlled randomised double-blind trial on the safety and immunogenicity of three different formulations of BBV152 reported the results of the trial on 375 participants, with one adverse event during the trial which was found to be unrelated to the vaccine.

The indigenous COVID-19 vaccine is being developed by a partnership between the Indian Council of Medical Research (ICMR) and Hyderabad-based company Bharat Biotech. A preprint is a version of a scientific manuscript posted on a public server prior to formal peer review.

The preprint paper on MedRxiv, a free online archive on preprints in the health sciences, noted: “Reactogenicity was absent in the majority of participants, with mild events. The majority of adverse events were mild and were resolved. One serious adverse event was reported, which was found to be unrelated to vaccination. All three vaccine formulations resulted in robust immune responses comparable to a panel of convalescent serum.”

Researchers from Bharat Biotech, ICMR, All India Institute of Medical Sciences (AIIMS) New Delhi and Patna, and several other institutes, participated in the analyses.

“We conducted a double-blind randomized controlled phase 1 clinical trial to evaluate the safety and immunogenicity of BBV152. A total of 375 participants were randomized equally to receive three vaccine formulations. Vaccines were administered on a two-dose intramuscular accelerated schedule on day 0 (baseline) and day 14. The primary outcomes were reactogenicity and safety,” noted the study.

It added that the secondary outcomes were immunogenicity based on the anti-IgG S1 response (detected with an enzyme-linked immunosorbent assay or ELISA, and wild-type virus neutralisation or microneutralisation and plaque reduction neutralisation assays). Cell-mediated responses were also evaluated.

The paper states that, to date, 180 vaccine candidates are being developed to prevent the coronavirus disease 2019 (COVID-19). The virus strain (NIV-2020-770), isolated from a COVID-19 patient and sequenced at the ICMR-National Institute of Virology (NIV), was provided to Bharat Biotech.

Bio-Safety Level-3 manufacturing facilities and a well-established Vero cell manufacturing platform, with proven safety in other licensed live and inactivated vaccines, aided in the rapid development of BBV152.

One serious adverse event was reported. The participant was vaccinated on July 30. Five days later, the participant reported symptoms of COVID-19 and was found to be positive for SARS-CoV-2, according to the findings. The symptoms were mild in nature, but the patient was admitted to hospital on August 15. The participant was discharged on August 22 following a negative nucleic acid result. The event was not causally associated with the vaccine, the findings showed.

To ensure generalisability, the trial was conducted on volunteers from diverse geographic locations and socio-economic conditions.

Bharat Biotech is currently conducting phase-3 trials of its vaccine and has applied to the Drugs Controller General of India for an emergency use authorisation, as have Pfizer and the Serum Institute of India for vaccines they are developing, respectively.


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Printable version | Jun 13, 2021 12:07:07 PM | https://www.thehindu.com/sci-tech/science/coronavirus-covaxin-phase-1-trial-results-show-vaccine-is-safe/article33348040.ece

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