Novel coronavirus vaccine for India?
One of the leading medical scientists of India, Dr Gagandeep Kang, in her recent interview with the Indian Express, said, “A good vaccine for India must be affordable and which can be made in large numbers. Ease of delivery is key and preferable as a single dose. One dose vaccine eases the burden on the immunisation program as it does not require tracking down the person for a second dose. It should also give long term protection.”
As of 3rd December 2020, UK has approved the Pfizer/BioNTech coronavirus vaccine and paved the way for mass vaccination for its citizen. Two other vaccines, one from Moderna and another from Oxford-AstraZeneca, have reached the final stage of their phase 3 trials. What does that mean for Indians? Will we be able to get any of them? Will it be feasible and affordable for the citizen of India to buy them or the Indian government to provide it to the ‘rural’-zen of India?
Keeping these thoughts in mind, in this article, I will analyse, if India will be able to afford any of the four vaccines from Pfizer-BioNTech, Moderna and Oxford-AztraZeneca (OAZ).
Based on the preliminary finds of their final clinical trials, both Pfizer-BioNTech and Moderna vaccines have shown >90% efficiency. Both are messenger RNA (mRNA) based vaccines and offer great promises. Making mRNA vaccines does not require time-consuming steps, such as growing ingredients in animals. They can also be designed at a faster pace than the traditional vaccines. For example, the Moderna vaccine was designed in two days.
Both of these mRNA vaccines require two doses: Pfizer’s booster shot is spaced by three weeks after the first one; Moderna’s second shot is administered four weeks after the first one. Dual dose requirement needs more storage facility, which is a critical parameter during the delivery and dissemination of vaccines.
The Moderna vaccine, which is stored frozen at -20 degrees Celsius, can also be kept in refrigerator for a month. Possibility of storage at 4 degrees makes its distribution to the rural areas easier and ensures wider distribution. But, the high price of the vaccine ($37) may limit its usage in private domain.
The vaccine from Pfizer and BioNTech, priced at $19.50, is stored at ultracold, -70 degrees Celsius. Although the company has created its own GPS-tracked coolers filled with dry ice, the process of distribution may not be feasible for tropical countries like India, 8 million vaccination location are covered by 28,000 cold-chain points. And, even if we try to count on these cold chain points, the existing vaccine storage system does not support long term storage at -70 degrees.
The third vaccine which joined the efficiency lane, the Oxford-AstraZeneca (OAZ) is 70% effective, according to the preliminary analysis of its third phase results. But, then AztraZeneca declared, that this efficiency result is an average of two separate tests which comprised of 2 dosages, each 2 weeks apart. Test 1: 1 half & 1 full dose; Result: 90% efficient. Test 2: 2 full dosages; Result: 62% efficient. Astonishingly, the low dosage was a manufacturing error, as admitted by the company.
Keeping all these complications aside, OAZ vaccine is priced around $3 and is stable at refrigerator temperatures (4 degrees) and hence, easier to disseminate in the tropical regions using the existing vaccine storage and distribution chains. Based on the large efficacy trials in UK, Brazil, South Africa and USA, no participants who received the vaccine were hospitalized or developed severe COVID-19. Early assessment suggests that this vaccine may even prevent transmission of the virus from people with no symptoms also.
AstraZeneca estimates that it will have 200 million doses ready worldwide by the end of 2020 and capacity to produce 100 million to 200 million doses per month once production is ramped up. Thus, more doses of the vaccine may be available sooner.
So, of these three, will India be getting any?
Serum Institute of India (SII), Pune, the world’s largest vaccine manufacturer by volume, and Indian Council of Medical Research (ICMR), the apex body in India for biomedical research is conducting the phase 3 clinical trials (OAZ) vaccine at 15 different centres, across the country. 1600 participants have been enrolled for the purpose. SII has already manufactured 40 million doses of the vaccine. The promising result of the trials so far give confidence that OAZ vaccine could be a realistic solution to the deadly pandemic.
But, at $3 per dose per person, this vaccine is still the most expensive vaccine that India has seen so far. Being a double dose vaccine, it would also require people tracing and one has to double the cost of the vaccine.
Considering the vaccine prices, the indigenous vaccine from Bharat Biotech seems to be a more promising choice. Bharat Biotech has recently begun Phase 3 clinical trials in 26,000 participants in over 25 centres spread across 6 states in India. Being an inactivated vaccine, the exisiting technology, the storage and delivery conditions of this vaccine is same as that of the OAZ vaccine. However, it is also a 2-dose vaccine and would require people tracing just like the other three.
May be in the first vaccine wave, one of these vaccine will be a prefered choice for the COVID-19 frontline workers, but for larger public roll outs, a preferable vaccine must come from single dose vaccines. For now, vaccines developed using measles virus or vesicular stomatitis virus or replicating vector adenovector virus or protein vaccines with an adjuvant offer potential to be a single dose vaccine.
While the wait for a suitable vaccine for tropical parts of the world is still on, a cautionary behaviour is highly recommended! Limited vaccine doses, even after the approval, requires people to continue wear masks and socially distance. Immunisation of larger population will take time and hence, it may still be months to stop the virus from spreading. The goal of the immunisation program is to immunize enough people to achieve herd immunity.
Writer of this commentary is Surabhi Sonam, PhD, who is an Assistant Professor at D Y Patil International University, Pune, India. She is a bioengineer with a special interest in scientific communication. She obtained her PhD from Mechanobiology Institute, National University of Singapore and then did post-doctoral research for 3 years in Institut Jacques Monod, Paris, France before returning back to India to pursue her career in teaching and research.
