Hope floats for Covid-19 vaccine candidates in India

If the beginning of last year was all about New Year resolutions, the beginning of this year has been all about tracking the progress of Covid-19 vaccines. Since the beginning of the pandemic last year, the development of a vaccine has been the ray of hope that has sustained the world. Along with the World Health Organization, common people have been tracking the development of a vaccine with bated breath. And all this seems near fruition now, at least for the people in India.

On Sunday, India’s drugs regulator, the Drugs Controller General of India (DCGI) gave the nod for emergency use to two vaccine candidates: Covishield, the Covid-19 vaccine developed jointly by AstraZeneca and Oxford University, which is manufactured in India by Adar Poonawalla’s Pune-based Serum Institute of India; and Covaxin, the indigenous vaccine developed by Hyderabad-based Bharat Biotech in collaboration with the Indian Council of Medical Research (ICMR) and the National Institute of Virology (NIV), Pune. The roll-out of phase 1 of the vaccination process is expected to begin in the next few days.

“There is enough vaccine supply for the first phase of the roll-out. You will see the public and private healthcare workers, all 3 crore (30 million) get vaccinated,” Dr V.K. Paul, chairman of the National Expert Group on Vaccine Administration for Covid-19 (NEGVAC) and member (health) at government think tank NITI Aayog, tells Fortune India. NEGVAC's aim is to guide all aspects of introduction of the Covid-19 vaccine. The first phase of the vaccination process is expected to cover 300 million people.

Besides Covishield and Covaxin, Pfizer had also applied for emergency use authorisation (EUA) of its vaccine candidate, which it has developed with BioNTech. An expert committee of the Central Drugs Standard Control Organisation (CDSCO) met on January 1 and 2, reviewed data on safety and efficacy presented by the companies and recommended giving approval to Covaxin and Covishield. According to sources, more data is awaited from Pfizer.

Phase 3 trials for the Covaxin vaccine candidate, which began in November, are currently being conducted in 23,000 subjects. This country's first indigenous vaccine is derived from a strain of SARS-CoV-2 (the Covid-19 virus) isolated by ICMR and NIV. The Covishield vaccine candidate was approved after providing data generated from 23,745 participants overseas, and 1,600 participants in India, the DCGI said. The vaccine is based on a chimpanzee adenovirus called ChAdOx. Both are two-dose vaccines and can be stored at 2°-8° Celsius. The clinical trials will continue even as the vaccinations begin.

The expert committee has also given the nod for phase 3 clinical trials of Zydus Cadila’s ZyCoV-D, a DNA-based vaccine candidate. The company had sought permission to conduct phase 3 trials in 26,000 participants in the coming months after submitting data for phase 1 and phase 2 trials in 1,000 participants. This is a three-dose vaccine.

With the approval of the two vaccines, preparations are on to roll out batches over the next few weeks. Meanwhile, the states have been doing dry runs to identify glitches since the last two weeks.

As the vaccinations are expected to be done over the next few months, at what numbers will India begin to see herd immunity?

“With a dense population of over a billion, 60%-70 % of the population needs to have antibodies to justify herd immunity,” says Manindra Agrawal, a professor at IIT Kanpur and member of a committee constituted by the Department of Science and Technology to develop a mathematical model on Covid-19 progression. But there are riders. “Healthcare professionals meet and interact with a large number of people, so vaccinating them reduces the risk of spreading infection faster,” Agrawal added.

However, that's not to say that a fool-proof method has been found to counter Covid-19. The working of the vaccine, its effectiveness, and the protection it offers are all works in progress. And they will continue to be so for at least another two years.