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Covaxin: Have Clinical Trials Concluded? How Safe Is the Vaccine?

What type of vaccine is it? How does it work? Here’s all you need to know.

Updated
India
3 min read
When will it be available? How much will Covaxin cost? Do we know enough about its efficacy and safety yet?
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Just days after Bharat Biotech’s ‘Covaxin’ became India's first indigenously produced vaccine against the novel coronavirus to get 'emergency approval for public health interest,' the Centre on Saturday, 9 January announced that India’s vaccination drive will begin from 16 January.

The vaccine has been developed by pharma major Bharat Biotech in collaboration with Indian Council of Medical Research (ICMR) and National Institute of Virology (NIV).

What type of vaccine is it? How does it work? Is it safe? And have the trials been completed? Here’s all you need to know.

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What is the recommendation ‘restricted use in emergency situation in public interest as an abundant precaution’ really mean?

AIIMS director Dr Randeep Guleria, in an interview with NDTV, said that Serum Institute’s Covishield will be India’s go to vaccine. He said that Covaxin vaccine has been given “a limited approval to be used in case the Serum vaccine appears to be not that effective, or in case the UK mutant virus causes the number of cases to go up dramatically.” He also mentioned that data will continued to be collected and studied.

How does Covaxin work?

The SARS-CoV-2 strain for Covaxin was isolated in NIV, Pune and transferred to Bharat Biotech. The inactivated vaccine was then developed and manufactured in their High Containment facility in Hyderabad.

An inactivated vaccine or a killed vaccine uses the killed version of the pathogen that causes the disease. They are made from viruses or bacteria that have been killed clinically and therefore cannot cause diseases anymore, according to WHO.

Other inactivated vaccines include Hepatitis A, Influenza, Polio and Rabies among others.

Are clinical trials over for Covaxin?

No, phase III trials for Covaxin that began in November are still ongoing across 22 sites in India. After reports that clinical trial sites were struggling with recruitment, Bharat Biotech issued a statement saying they’ve recruited 23,000 volunteers of the 26,000 required to carry on the trials.

The vaccine was evaluated in 1,000 subjects in Phase I and Phase II clinical trials.

What efficacy does the vaccine offer? Has the data been peer reviewed?

We don’t exactly know. The company has submitted multiple data to the Subject Expert Committee (SEC) of the Central Drugs Standard Control Organisation (CDSCO). They’ve been asked to keep the SEC updated with all new information as it emerges. An efficacy of a vaccine can only be determined after it has gone through large scale phase III trials, which are still ongoing.

Covaxin has released phase 1 data which showed success in inducing an immune response and no serious adverse events in any of their 375 volunteers.

The interim findings of the phase 1 trial data were published in Medrexiv, and revealed promising results indicating a successful, tolerable vaccine.

The most common adverse event was pain at the site of infection, and as per the paper, this was resolved immediately.

The study is a preprint and has not been peer-reviewed.

Earlier, a preprint of an animal study was released that also showed ‘robust immune response.’

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How safe is It?

According to reports, the company had an adverse event during the phase 1 trial in August when a patient - who had no comorbities - had to be hospitalised with viral pneumonitis. However, this was not revealed to the public.

“The adverse event during phase I clinical trials during August 2020 was reported to the CDSCO-DCGI within 24 hours of its occurrence and confirmation. The adverse event was investigated thoroughly and determined as not vaccine related,” Bharat Biotech said in a statement.

The company added that it got an approval for the next two phases of clinical trials only after a detailed investigation of the incident was completed.

(The article was first published in FIT and has been republished with permission)

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