Pfizer to Covaxin: An account of Covid-19 vaccine candidates for India

Being one of the worst-hit countries with coronavirus cases still rising in huge numbers, India is curiously waiting for a promising announcement with approvals by regulatory authorities monitoring the progress of several vaccine candidates. India’s realistic hopes, however, hinge heavily on 3 to 5 vaccine candidates.

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Huge population makes India’s requirement very heavy for the firms to promise an early delivery of the Covid-19 vaccines. (Photo for representation: Reuters)

Excitement over early arrival of a Covid-19 vaccine on the horizon is suddenly soaring high. There is a Pfizer, then there’s a Moderna, also a Sputnik and Oxford-AstraZeneca anticipating to launch Covid-19 vaccines before the end of the year.

Being one of the worst-hit countries with Covid-19 cases still rising in huge numbers, India is curiously waiting for a promising announcement with approvals by regulatory authorities monitoring the progress of several vaccine candidates. India’s realistic hopes, however, hinge heavily on three-to-five vaccine candidates.

Serum Institute of India

The Serum Institute of India is in tie up for two Covid-19 vaccines — being developed by Oxford-AstraZeneca and Novavax.

Covishield is the local brand name for AstraZenerca’s Covid-19 vaccine. It is in the most advanced stage of human trials in India — nearing completion. The ICMR has been monitoring its progress and expressed satisfaction with results.

If all goes well, the Serum Institute of India can start distributing the vaccine by the year-end. This means it may be available — maybe not on mass scale — for inoculation around the same time as Pfizer’s vaccine in the US.

Photo for representation (PTI)

The Serum Institute has entered into an agreement with the AstraZeneca for producing 1 billion doses of the vaccine. Indian government has placed a demand for 500 million doses of this Covid-19 vaccine.

With Novavax, the Serum Institute has an agreement of producing 2 billion doses a year. India has placed a demand for 1 billion doses of the Covid-19 vaccine being developed by Novavax. The vaccine candidate is in the second and third phase of trials. It is likely to be commercially available around mid-2021.

Bharat Biotech and ICMR

Bharat Biotech and the ICMR have collaborated to develop indigenous Covid-19 vaccine, to be called Covaxin. It has entered the third phase of trials with 26,000 participants.

This vaccine is being developed from an inactive strain of the SARS-CoV-2, the coronavirus that causes Covid-19. The strain was isolated from an asymptomatic person at a containment facility in Hyderabad in May this year.

Covaxine is different from other potential vaccine candidates for India for being a direct strain isolated from the disease causing coronavirus. Novavax is developing its vaccine by growing harmless copies of the coronavirus spike protein and packaging them as nanoparticles. Covishield is being developed from a weakened strain of the common cold virus, adenovirus.

Zydus Cadila

Gujarat-based Zydus Cadila began developing another indigenous Covid-19 in July. It is developing the vaccine on the same DNA-based technique it used to develop the vaccine for Hepatitis C which has been marketed since 2011.

Photo for representation (PTI)

Its second phase was launched in August and the third phase is expected to begin in December. The vaccine is not expected before the first quarter of the next year.

Sputnik-Dr Reddy’s

In August, Russia announced a breakthrough in Covid-19 vaccine development. It registered its vaccine under the name of Sputnik V, developed by Gamaleya Research Institute (GRI) and funded and promoted outside by the Russian Direct Investment Fund (RDIF).

In India, the RDIF’s partner is Dr Reddy’s Laboratories for conducting clinical trials. The second and third phases of trials are expected to begin early next month. The vaccine development is based on a complex technology in which another virus is employed to carry the DNA code required for triggering immune response in cells.

Pfizer and Moderna

These two companies have claimed close to 95 per cent success for their vaccine candidates. Sputnik V had 92 per cent success rate. Both Pfizer and Moderna are developing their Covid-19 vaccine on mRNA technology. If approved these would be the first-ever vaccine based on mRNA technology.

Photo for representation (AFP)

Use of mRNA means these two vaccines use synthetic genetic material instead of strain from the actual virus in order to prepare the body’s immune system to the real SARS-CoV-2 coronavirus.

So, which one is the best for India?

Going by the technological and logistical requirements, the vaccines to be distributed by the Serum Institute of India and the Bharat Biotech are best suited for the country — Covishield, Novavax and Covaxin.

All three require storage at 2-8 degree Celsius. This is the same requirement as needed for polio vaccine. India has robust infrastructure for storage and distribution of such vaccines.

Sputnik V requires storage at minus 18 degree Celsius, and it is in the process of developing a freeze-dried form of vaccine. That is, it will be frozen as powders and require a liquid to be added before being injected.

Why not Pfizer or Moderna?

The vaccine being developed by Moderna can be stored at the same temperature for 30 days not longer. Given the logistical infrastructure for import-to-transportation in India, distributing Moderna’s vaccine to the remotest villages of India would be a challenge.

Photo for representation (PTI)

The normal requirement for vaccines being developed by both Moderna and Pfizer is minus 70 degree Celsius. Moderna’s can also be stored at minus 20 degree Celsius.

These two drugmakers don’t yet have an Indian partner. The government is in talks with these firms for an arrangement to procure Covid-19 vaccines. However, the companies have already committed millions of doses to several other countries, which would get the vaccine before India’s turn comes up. Huge population makes India’s requirement very heavy for the firms to promise an early delivery of the Covid-19 vaccines.

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