Covaxin, the earliest indigenous vaccine of India has presented its most awaited phase-3 efficacy results after being in discussion for not providing its complete reports. The vaccine presented a good result of 77.8% and also fared well against the Delta variant. This article summarises the study of phase-3 of the vaccine trial and also throws light on comparison with other vaccines. 

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

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The study

The CDSCO's Subject Expert Committee (SEC) accepted phase-3 efficacy data for Covaxin, on 22nd June. On July 3, Hyderabad-based Bharat Biotech India Ltd (BBIL) announced the long-awaited findings of Covaxin's phase-3 study, which included over 25,800 volunteers across 25 hospitals in the nation. 

Covaxin, the country's first indigenous COVID-19 vaccine, was created utilising seed strains obtained from the National Institute of Virology (NIV) and based on the Whole Virion Inactivated Vero Cell platform technology. 25800 individuals volunteered for the phase-3 studies. Bharat Biotech provided the data that indicated 77.8% effectiveness.

The organization said that in collaboration with experts at the Indian Council of Medical Research, the vaccine had an overall effectiveness of 77.8 per cent against symptomatic COVID. This is greater than the overall effectiveness of 70.4 per cent revealed in January by AstraZeneca (Covishield) Phase-3 study findings.

Covaxin is the first approved COVID-19 vaccine to demonstrate potential effectiveness against asymptomatic infections, according to Bharat Biotech. This, the company stated, will contribute to the reduction of disease transmission.

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Effectiveness

Bharat Biotech revealed in April that Covaxin had a 78 per cent effectiveness rate, based on interim results from 127 symptomatic COVID-19 cases among phase-3 study participants. The firm stated that in phase-3 studies, the vaccine exhibited 100 per cent effectiveness against severe instances. Bharat Biotech has enlisted 25,800 participants between the ages of 18 and 98 years as part of the trial.

Additionally, the two-dose vaccination was efficacious against severe illness and protective against asymptomatic COVID in 93.4 per cent of cases. Furthermore, it was 65 per cent protective against the coronavirus's Delta form, which is the most prevalent in India and is associated with an increasing number of cases in Europe and the United States. According to the preprint, the vaccination was 67.8 per cent effective in individuals 60 years and older and 79.4 per cent effective in younger persons.

“Safety analysis indicates that adverse events recorded were comparable to placebo (or those who received a dummy dosage), with 14% of participants having commonly reported side effects and fewer than 0.5% suffering severe adverse events,” the firm stated in a statement.

Bharat Biotech initiated the volunteer recruitment process in November 2020 and concluded the exercise in January. While it received emergency use authorization that month, there was criticism because the effectiveness results were considerably delayed in comparison to many other vaccines — AstraZeneca, Pfizer-BioNTech, Moderna, and Novavax.

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How does Covaxin fare compared to other vaccines?

Covaxin vs Covishield: If Covaxin's effectiveness was found to be 77.8% in the end, that's a good result. Covishield is Covaxin's major competitor in India (AstraZeneca-Oxford COVID-19 vaccine). After more than 14 days and two doses, it had a 76 per cent overall effectiveness against symptomatic COVID-19 patients. Vaccine effectiveness is 81.3 per cent in volunteers who received the first and second doses within a 12-week interval or longer. The WHO has given its approval to Covishield.

Covaxin vs SputnikV: The latter has a 91.6 per cent effectiveness rate, according to the statistics. The WHO has yet to accept Sputnik V for emergency listing.

Covaxin vs Pfizer & Moderna vaccines: After the second dosage, Pfizer and Moderna's mRNA vaccines have 95 per cent and 94 per cent effectiveness, respectively. The vaccine from Pfizer demands a storage temperature of -70 degrees celsius.

Covaxin vs J&J vaccine: The WHO has approved Johnson & Johnson's single-dose COVID-19 vaccine, which provides 66 per cent protection against moderate to severe COVID infections.

Covaxin vs Sinopharm & Sinovac: According to initial data, the two Chinese vaccines designated for emergency use by WHO namely, Sinopharm and Sinovac had effectiveness rates of 79 per cent and 54 per cent, respectively.

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How does Covaxin counteract the Delta variant?

Another fascinating element of Covaxin is its effectiveness against variants of concern (VoC), particularly the Delta form, which has recently become prevalent. Novavax protein subunit vaccines' latest phase-3 efficacy data attempted to map vaccination effectiveness on VoCs.

They sequenced the positive clinical trial patients to see how well the vaccination protects against the variations. Except for AstraZeneca's (Covishield) and Pfizer's vaccines, we lack evidence of their efficacy against the Delta variant. The effectiveness of the majority of COVID-19 vaccinations against the Delta variant decreased.

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Accelerating the WHO's emergency listing process

The phase-3 effectiveness findings will strengthen Covaxin's case for WHO emergency use designation, which is crucial for worldwide adoption of the indigenous COVID-19 vaccine. Covaxin's pre-submission meeting is set for June 23rd. The WHO has accepted Covaxin's Expression of Interest (EOI). The worldwide organisation has requested further information from the Indian firm.

Following the pre-submission meeting, WHO will accept the dossier for assessment and assign a targeted action date or expected decision date. According to the WHO, only COVID-19 vaccines that have been subjected to phase IIb or phase III trials and submitted to the relevant NRA (National Regulatory Agency) are being considered. The WHO will not include the vaccination until the vaccine has been authorised by the relevant national regulatory authority.

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International front

Dr Balram Bhargava, Director General of the Indian Council of Medical Research, stated in reaction to the new effectiveness findings that Covaxin will "significantly help to protect the world population against the deadly SARS-CoV-2 virus" in addition to aiding Indian residents.

“I am happy to report that Covaxin, created via an efficient public-private collaboration between ICMR and Bharat Biotech, exhibited overall effectiveness of 77.8 per cent in India's largest COVID phase 3 clinical study to date. Our experts at ICMR and BBIL have worked diligently to develop a vaccination that is genuinely efficacious and meets all international safety requirements. The successful creation of Covaxin has enhanced India's academic and industrial standing in the global arena," Dr Bhargava stated.

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What's the upcoming step?

Clinical studies to determine Covaxin safety and effectiveness in children between the 2 and 18 years of age are conducted by Bharat Biotech. There is also a clinical investigation for the safety and immunogenicity of a booster dosage.

Variants of concern are being studied and assessed for their appropriateness for follow‐up booster dosages, the firm added. The research is underway.

Covaxin is produced by Bharat Biotech at four plants in India. As far as production is concerned. By the end of this year, the firm intends to attain a yearly capacity of 1 billion doses. Since January, India has received fewer than 4 crore doses of Covaxin. According to the company, it can generate over six crore doses per month and will scale up to ten crores by September.

Covaxin has been approved for emergency use in 16 countries, including Brazil, India, the Philippines, Iran, and Mexico, and approval in another 50 countries is pending.

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Refer to part one of this article here

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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.