Saturday, 28 Nov, 7.56 am Deccan Herald

DH Deciphers | How effective are Covid-19 vaccines and when will India get them?

Kalyan Ray,

The news of the high efficacy of four Covid-19 vaccines in the last two weeks has generated hopes at a time when the pandemic has infected more than 93 lakh Indians and killed over 135,000 of them. But notwithstanding the promises, Covid-19 shots are unlikely to be available to the people immediately as there are multiple hurdles that need to be overcome. Here's what you need to know:

How many Covid-19 vaccines are available now?

While vaccine development usually takes years, the global emergency caused by the coronavirus has greatly expedited the process in the last 12 months. Forty-eight vaccine candidates are in clinical trials, including 11 under phase III. (Under Phase I, the vaccine is usually tried out on 30-50 people to check safety; Phase II involves a larger trial to evaluate immune response while Phase III usually involves tens of thousands of people to examine if a vaccine is really protecting people from the infection.)

Early results from vaccines developed by BioNTech-Pfizer, Moderna, AstraZeneca-Oxford University and Russia's Sputnik V have shown promises. An Indian vaccine developed by Bharat Biotech is in Phase III trial while a second one from Zydus Cadila is undergoing clinical evaluation. Hyderabad-based Biological Evans will also launch the trial of a vaccine developed by Johnson & Johnson.

How promising are the early results?

BioNTech-Pfizer, Moderna and Sputnik V vaccines claimed more than 90% efficacy while AstraZeneca claimed 70% efficacy. But even the AstraZeneca vaccine was seen to be 90% effective under a specific dose regimen. The problem, however, is that these are based on interim data as technical details on the trial protocols and findings have not been published in any peer-reviewed journal. (Peer review is the evaluation of a scientific work by others working in the same field). Since the devil always lies in the details, a clearer picture of the vaccine efficacy would emerge when the publications appear.

When would the vaccine be available in India?

That's difficult to say even though Adar Poonawalla, the CEO of the Serum Institute of India, promised to make 100 million doses (of the AstraZeneca vaccine) available to India by late December 2020 or early January 2021. He also promised 400 million doses by July 2021. The government plans to use these doses for emergency use for doctors, healthcare workers and some of the vulnerable people. India is, however, yet to finalise the pathway to the emergency user authorisation. Once it is finalised, the SII will have to apply for EAU approval for its vaccine. While the timeline for public access to the vaccine remains unclear, researchers estimated that it may take up to two years to vaccinate nearly 800 million Indians in order to reach herd immunity.

Which vaccine would be used in India?

The AstraZeneca is the best bet at the moment despite its somewhat lower efficacy because it is easier to transport using India's existing cold chain network, and the manufacturer has made a commitment to make 50% of its capacity available to India. The next best options are Sputnik-V and Bharat Biotech and Zydus Cadila products, subject to the trial outcomes. The Moderna and Pfizer shots are unlikely to come to India in the near future because of their: (a) high cost (b) ultra-low cooling requirement for storage and (c) pre-booking of their entire stock by the rich nations. The USA has promised Pfizer a $1.95 billion contract for 100 million doses, which would mean the company's entire production capacity for 2020 and another 50 million in 2021. The US booked 800 million doses so far whereas the UK with a population of 67 million pre-booked 325 million doses. Australia with less than 30 million population pre-booked 84 million doses.

Does India have adequate infrastructure to roll out an adult vaccine to such a large population?

The infrastructure at the moment is inadequate. Currently, there are 28,000 cold chain points and 700 plus refrigeration vans. The government is in talks with the private sector for additional cold chain facilities. State governments have also been asked to prep up their cold chain network. Also, there are 70,000 plus trained vaccine-givers but efforts are underway to find out more people to administer the two-dose vaccine.

How much would the vaccine cost in India?

For a two-dose regimen, the AstraZeneca vaccine would cost $8. Poonawalla said he would sell the vaccine at Rs 1,000 while talks are on with the health ministry to fix a procurement rate for the government. Sputnik-V will cost less than $20 for two doses while Moderna and Pfizer products will cost $30 and $39, respectively.

Disclaimer: This story is auto-aggregated by a computer program and has not been created or edited by Dailyhunt. Publisher: Deccan Herald