Covaxin, one of the two homegrown vaccines for coronavirus has been discussed a lot lately, especially due to the incomplete third phase trial reports. This article brings forward the data about the previous trials in various publications and the study about its efficacy against COVID variants.

For our comprehensive coverage and latest updates on COVID-19 click here.

Bharat Biotech, India's first indigenous COVID-19 vaccine producer, recently published detailed data from all Covaxin research projects. According to the firm, the whole data for Phase I and II trials of Covaxin, as well as partial data for Phase III studies, have been extensively scrutinised by Indian regulators.

India began its COVID-19 immunisation campaign on January 16, 2021, using two vaccines: Covaxin and Covishield from the Serum Serum Institute of India. Covaxin, a whole-virion inactivated coronavirus vaccine, is the first and only product in India to have human clinical trial data published, according to Bharat Biotech. The announcement said that the complete data from trials on Covaxin's neutralisation of variations are already available on bioRxiv, Clinical Infectious Diseases, and Journal of Travel Medicine. According to Bharat Biotech, "The study on the neutralisation of Beta and Delta variants (B.1.351 and B.1.617.2, respectively), as well as the study on the B1.1.28 variant, were published in Journal of Travel Medicine, while the studies on the B.1.617 variant and the Alpha variant (B.1.1.7) were published in Clinical Infectious Disease and Journal of Travel Medicine, respectively."

1. It is the first and only product in India to have any human clinical trial data released.
2. Covaxin is the only product with evidence on developing variations and the first and only COVID-19 vaccination with effectiveness evidence in Indian populations, according to a statement from Bharat Biotech.

Preclinical studies are used to evaluate vaccine candidates in laboratory animals during the vaccine development process. "The published findings are frequently referenced as evidence of Bharat Biotech's rigour and breadth in conducting clinical trials. Currently, results from Covaxin's Phase III trial's effectiveness and safety follow-up are being examined and collated. To demonstrate its unwavering commitment to honesty, the organisation will shortly make the final analytical data from Phase III studies public.

Bharat Biotech has performed three preclinical investigations that have been published in the peer-reviewed journal Cellpress. Covaxin's Phase I clinical trial (conducted to assess a vaccine's safety, immune response, and optimal dosage) and Phase II clinical trial (conducted to assess the vaccine's safety and ability to generate an immune response) are published in the peer-reviewed journal Lancet-Infectious Diseases, according to the statement.

What kind of protection does Covaxin offer against the delta variant?

In a study released as a preprint publication on June 7, researchers from Bharat Biotech and the Indian Council of Medical Research (ICMR), which created Covaxin jointly, tried to answer this issue.

What exactly did they come across?

The main finding was that, on average, sera from vaccinated persons were 2.7 times more neutralising against the B.1 variation than the delta version. On average, sera from COVID-19 survivors were three times more neutralising against the B.1 version than the beta version.

The sera exhibited a weaker neutralising impact against the beta and delta variants than they did against the B.1 strain. Given the fact that immunological protection against the delta version was reduced after both Covaxin dosages, the authors claim that its neutralisation potential is well established.

The study's ramifications

Antibodies' neutralising impact after Covaxin was clearly weaker against the delta version than against the B.1 version. Is this to say that Covaxin is ineffective against the delta variant? This has been covered by a number of news sites. However, we know very little about the association between circulating antibody levels and infection protection thus far.

We have to rely on well-conducted scientific trials (including a placebo group) to show efficacy exactly because we don't completely understand this link. It's also worth noting that this research, like a few others, only looked at humoral immunity or immunity provided by circulating antibodies that try to keep the virus from entering cells and thereby preventing symptoms. This is distinct from T-cell immunity, which is more difficult to examine in the lab and occurs after the cells have been infiltrated and aim to avoid serious sickness and death.

To seek for and investigate T-cell immunity, phase 3 clinical studies are more appropriate. Case-control studies, such as the one done by Public Health England to assess the real-world efficacy of the Pfizer-BioNTech and Oxford-AstraZeneca vaccines, are the next best choice.

Overall, the research provides no data to back up the authors' assertion that sera derived from vaccinated subjects had “well-established” neutralisation capability against the beta and delta alleles. The study found that Covaxin's neutralisation efficiency against the beta and delta variants is significantly lower than against the B.1 strain. The majority of this research team is also working on Covaxin's phase 3 clinical trial. The experiment enrolled participants between November 16, 2020, and January 7, 2021, and the study investigators tracked the cohort of 25,800 people through the worst of India's second wave.

If the follow-ups were as flawless as possible, and if the firm and/or ICMR analysed the genomes of the viral samples that infected individuals of the cohort, this study group is banking on a treasure of data. This information might help address important issues concerning the vaccine's effectiveness in preventing various degrees of disease following infection with the delta version.

As a result, the best thing the ICMR and Bharat Biotech could do is speed up the examination of the phase 3 trial data and publish the findings. There is nothing that will recompense the selflessness of the thousands, and nothing less, that will please the many millions of Indians who took Covaxin for their trust.

Additionally, the pharmaceutical company claimed that the Phase III final analysis results would be available shortly. "The final analysis will require effectiveness and two-month safety data for all patients. This is the case with the CDSCO and the USFDA, according to the firm. "The final analysis will be submitted to CDSCO, followed by peer-reviewed journal submissions and media distribution," the statement continued.

The remark comes a day after the US Food and Drug Administration (USFDA) denied Bharat Biotech's application for an emergency use authorisation (EUA) for Covaxin, therefore postponing the vaccine's availability in that nation. Following the decision by the US Food and Drug Administration, Ocugen, Bharat Biotech's US partner, stated that the business will now pursue full clearance for Covaxin.

Bharat Biotech has said that it will conduct clinical trials in the United States to support Covaxin's marketing application in the nation. Regarding the Phase 3 clinical trial results, Bharat Biotech stated that it had disclosed detailed data from all Covaxin research trials with Indian regulators.

It's worth noting that Bharat Biotech is the exclusive manufacturer of Covaxin, India's COVID-19 vaccine, which was developed in-house.

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.

The author is a practising super specialist from New Delhi.