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Experts point to concern over ‘limited data’ for Covaxin


The emergency use approval in India for the Serum Institute of India (SII) vaccine against Covid-19 developed by AstraZeneca and the University of Oxford, and the “restricted use in emergency situations” consent for the locally developed vaccine from Bharat Biotech International Limited has sparked a debate among experts, particularly over the decision to approve the Bharat Biotech vaccine despite the shorter duration of human trials and relatively less data.

India’s nationwide vaccination campaign is scheduled to start in January with the AstraZeneca-Oxford injection. The Bharat Biotech vaccine, according to experts at the time, is a backup under clinical trial conditions if an increase in cases causes the need for doses.

AstraZeneca-Oxford was approved by Drug Control General of India based on safety, immunogenicity and efficacy data generated on 23,745 study abroad participants, as well as interim data from phase 2/3 trials on 1,600 people in India. What prompted his case was that it received approval last week from the UK’s Medicines and Healthcare Products Regulatory Authority.

The Bharat Biotech vaccine was approved for “restricted use in emergency situations of public interest as an abundant precaution, in clinical mode, especially in the context of infection by mutant strains” based on safety and immunogenicity data from tests performed on mice, rats, rabbits, Syrian hamsters and so-called challenge studies in macaques and rhesus hamsters, and phase I and phase II clinical trials in about 800 participants, according to the drug regulator.

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Early-stage trials found the vaccine to be safe and capable of invoking a robust immune response, but Phase 2 data is under peer review and has not been published. The phase 3 trials were announced on November 16 and about 22,500 of the 25,800 volunteers have enrolled, of whom about half have received two doses.

“The terminology is very different for the two vaccines, so it recognizes that the research stages for the two vaccines are different. The government will start vaccinating with the Serum vaccine in the first few weeks and will keep the Bharat Biotech vaccine as a backup until the data becomes robust at the end of this month or the beginning of the next, ”said Dr. Randeep Guleria, director of the Institute. of Indian Medical Sciences (AIIMS), New Delhi.

“The authorization for emergency use is standard, which Serum has. The assent of emergency situation for Bharat Biotech means that if there is an increase in the number of cases or if there are problems with the efficacy of the vaccine as far as the former is concerned, then the vaccine can be used in a clinical trial situation, as to be closely monitored because the data is not enough. It is a backup plan for a possible increase in cases, as in the UK, where they have changed the vaccination schedule from four to 12 weeks because they want to vaccinate as many people as possible. If we find ourselves in a similar situation, we will not be able to do it with a single vaccine. This (approval) is just to tell you, okay, go ahead, your current data is good, “he added.

However, some other experts argued that even in emergency situations, approval should be granted only after safety and efficacy have been irrefutably established.

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“It is absolutely shocking that the regulator has approved the Bharat Biotech vaccine, which has limited safety and immunogenicity data and no efficacy data. Phase 3 trials are still completing enrollment and it is too early for the data to meet the criteria for interim analysis. The only human data available on safety and immunogenicity are in 755 participants in phase 1 and 2 trials. This is equivalent to launching an untested and untested vaccine, ”said Malini Aisola, co-coordinator of All India Drug Action Network (AIDAN), which is a network of non-profit organizations that work to increase access and rational use of medicines.

The vaccines use two different and established delivery platforms. While IBS has a recombinant chimpanzee adenovirus vector vaccine (Covishield), Bharat Biotech has developed a full virion inactivated coronavirus vaccine (Covaxin).

“Covaxin is a whole virus inactivated vaccine with more potential to attack all parts of the virus rather than specific parts. This makes it a more effective tool against the new strain of virus found in the UK … even Pfizer recently said that it takes four to six weeks to adjust its vaccine to accommodate new mutations in the virus. ”Said Dr. Balram Bhargava, director general of the Indian Council of Medical Research, in an interview with HT. ICMR has also partnered to develop the vaccine.

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But other experts weren’t so sure.

“I am not aware of any data showing that Covaxin has any efficacy against any strain of the novel coronavirus, much less any special efficacy against the variant strain (from the UK),” said Dr. Gagandeep Kang, clinical scientist and professor of gastrointestinal sciences. . at the Christian Medical College, Vellore.

Both vaccines will be administered under government supervision and will not be available to the general public until data is complete and all trial results are available.

“The restricted emergency use authorization means that only the government will purchase the vaccines and decide who will receive them under supervision. Under restricted emergency use, these vaccines will not be commercially available, they will not be available to the public on demand. From what we know as of yesterday, there are no security issues. The government will give free vaccination to people for whom delayed protection may be denied, ”said Dr. T Jacob John, senior virologist and former professor at Christian Medical College, Vellore, Tamil Nadu.

Hindustan Times