- 16 May 2022
Bharat Biotech's Covaxin is yet to announce its Phase III results, however it has already struck deals with Brazil and USA to supply the vaccine. This comes after the famous British medical journal, Lancet, published a study on the effects of Covaxin, and said that the vaccine doses were well tolerated and only moderate vaccine-related adverse events were encountered. The randomised study was carried on 375 participants between the age of 18-55 across the country.
After striking deal with Brazil's
in January, Bharat Biotech signed a contract with US biopharmaceutical company
to co-develop, supply, and sell COVAXIN in the USA.
Image credits : ICMR
According to the leading British medical journal, Lancet, Covaxin (BBV152) is a whole-virion inactivated SARS-CoV-2 vaccine formulated with a toll-like receptor 7/8 agonist molecule adsorbed to alum (Algel-IMDG) or alum (Algel). A complete virus particle, outside the host cell, is known as a virion and an agonist is a molecule that can bind and activate a receptor to induce a biological reaction. The authorities conducted a double-blind(where a patient doesn't know if he or she is receiving the experimental treatment or a standard treatment), multicentre, randomised, controlled phase 1 trial to assess the safety and immunogenicity of BBV152 at 11 hospitals across India.
Immunogenicity measures the type of immune response that the vaccine generates and their magnitude over time. Healthy adults aged 18–55 years who were deemed healthy by the investigator were eligible. Individuals with positive SARS-CoV-2 nucleic acid and/or serology tests were excluded. Participants were randomly assigned to receive either one of three vaccine formulations (3 μg with Algel-IMDG, 6 μg with Algel-IMDG, or 6 μg with Algel) or an Algel only control vaccine group.
Image credits : ICMR
Findings and the subsequent inference
Between July 13 and 30, 2020, 827 participants were screened, of whom 375 were enrolled. Among the enrolled participants, 100 each were randomly assigned to the three vaccine groups, and 75 were randomly assigned to the control group (Algel only). Two intramuscular doses of vaccines were administered 14 days apart.
After both doses, solicited local and systemic adverse reactions were reported by 17 participants in the 3 μg with Algel-IMDG group, 21 in the 6 μg with Algel-IMDG group, 14 in the 6 μg with Algel group, and 10 in the Algel-only group. The most common solicited adverse events were injection site pain (17 [5%] of 375 participants), headache (13 [3%]), fatigue (11 [3%]), fever (nine [2%]), and nausea or vomiting (seven [2%]). All solicited adverse events were mild (43 [69%] of 62) or moderate (19 [31%]) and were more frequent after the first dose.
One serious adverse event of viral pneumonitis was reported in the 6 μg with Algel group, unrelated to the vaccine. Seroconversion rates (%) were 87·9, 91·9, and 82·8 in the 3 μg with Algel-IMDG, 6 μg with Algel-IMDG, and 6 μg with Algel groups, respectively. Seroconversion is the transition from the point of viral infection to when our bodies start developing detectable antibodies against the infectious agents.
"BBV152 led to tolerable safety outcomes and enhanced immune responses.", the report wrote. "The results reported here do not permit efficacy assessments. The analysis of safety outcomes requires more extensive phase 2 and 3 clinical trials," it said.
Efficacy against the New UK variant.
A preprint paper was published on January 26th, jointly by Bharat Biotech International Ltd, Indian Council of Medical Research (ICMR) and National Institute of Virology (NIV) assuring that Covaxin worked against the United Kingdom virus variant. The paper stated that 38 blood sera samples had been collected from Covaxin recipients who had returned from the UK and researchers found the neutralisation capacity of the antibodies against the UK variant was similar to that of the homologous variant otherwise circulating in India as well as two others found in the country.
Experts opine that the Covaxin, like the Moderna and Pfizer vaccines, also targets the spike protein, and hence the result of its efficacy against the UK strain is very much on the expected lines.
To know if the South African strain is a threat to vaccines, read here.
The Drug Controller General of India had granted restricted emergency use authorization to Bharat Biotech's Covaxin under the clinical trial mode. As per latest report of GOI, a total 283 lakh doses of Covishield and Covaxin vaccines have been transported to various parts of the nation and results have been encouraging. Out of which the government has procured about 55 million doses of Covaxin for the same. Luckily, no serious consequences haven't been reported yet.
It is indeed gratifying to see an indigenous vaccine feature in one of the most renowned journals across the globe where it shows promise and goodwill. The results till now, it does show that the vaccine was well-tested before it got rolled out for use and that might help us breath a trifle sigh of relief. Having said that, it doesn't abate all rooms for doubt about the efficacy of the vaccine until data of Phase III trials are out in the public domain, assuaging all fears once and for all.
This article uses research and inputs by Adrija Ray Chaudhury.