Updated: August 11, 2021 10:49:46 am
SARS-CoV-2 continues to play havoc in different parts of the world with several of its more virulent forms, particularly the Delta variant, now driving new waves of infections.
Vaccines developed against the virus are the most effective scientific intervention to control the pandemic. Developed at an amazing pace, as many as 19 vaccines have already been approved for immunisation in some part of the world or the other.
These vaccines are the result of intense scientific collaborations among scientists in academia and industry, and early huge funding from many governments. Unfortunately, the initial collaborative efforts did not translate into equitable access, and the trajectory of access has largely replicated the classical paradigm of developed and the underdeveloped parts of the world. Glaring disparities and differences in vaccine types, their availability and distribution have emerged in vaccination programmes across the globe.
The initiative COVAX, led by the World Health Organization (WHO), has struggled to procure and distribute vaccines to low- and middle-income countries.
While the western and resource-rich countries have mostly relied on the novel platforms of mRNA based vaccines from Pfizer and Moderna, and viral vector vaccines of AstraZeneca and Johnson & Johnson, the low- and middle-income countries find themselves relying mostly on vaccines developed in China and Russia.
As of now, around 4.1 billion shots of various vaccines have been rolled out worldwide, with China (1.61 billion), India (455 million) and USA (344 million) accounting for more than half of these. Many developed countries have vaccinated more than half their populations. On the other hand, resource-compromised countries have barely started their vaccination programmes.
The gap between supply and demand of vaccines needs to be filled quickly. Clearly, we need more vaccines, but where will they come from?
Virander S Chauhan is a former chairman of UGC and a former director of the International Centre for Genetic Engineering and Biotechnology. He is best known for his efforts towards developing a vaccine for malaria.
Vaccines in development
Among the 19 vaccines approved for use, a large number have been developed and approved in China, and more recently a few in developing countries such as Cuba, Iran, Turkey and Kazakhstan. In addition, more than 30 vaccines are in large efficacy trials with a few already waiting for emergency use approval. More than 90 vaccine candidates have entered phase I/II trials. Therefore more than 120 vaccines, including many in the developing world, are under development.
Given the fact that so far only five vaccines have been abandoned following clinical trials, many of these vaccine candidates are destined to reach the regulatory stages in various countries. Although currently there is a huge shortage in supply, the space for introducing new vaccines cannot be unlimited, and only the best may be able to compete with the existing ones.
Also, manufacturers of currently in-use vaccines have announced major increases in production at multiple locations. For example, Pfizer has recently announced production of its vaccine in South Africa, specifically for use in African countries. The most cost-effective vaccine of AstraZeneca, which is approved in more than a hundred countries, is already being manufactured in many countries.
There will be additional challenges for the new vaccines. The current first-generation vaccines were tested against the original strain of the virus, but phase III trials of the new vaccines will have to deal with multiple, highly infectious variants.
Further, organising large phase III trials in itself will become more complex, particularly in locations where a large proportion of adult populations are vaccinated and/or infection rates have significantly declined. Ethically too, phase III trials with placebo control groups may not be justifiable any more, given that efficacious vaccines are already in use.
Hopes & challenges
The next generation of Covid vaccines could address the issues of stability at higher temperatures for easy transportation and storage, a real concern in poor countries.
Large-scale immunisation through the injection route has always been complex and at least partly contributes to vaccine hesitancy. To avoid the needle and deliver vaccines through nasal or oral routes will also be an attractive target. Several non-injectable Covid vaccines are under development, including in India.
Perhaps the most exciting development in the new vaccine arena is the recent phase III trial results of the protein-based vaccine of Novavax, which has shown an efficacy of 91.4%. Importantly, these trials were conducted at a time when several virus variants had already emerged. However, the US regulator is yet to approve its emergency use.
Another protein-based vaccine being developed by Biological E in India, in collaboration with Baylor College of Medicine, US, has shown excellent safety and efficacy results in human trials conducted so far. Such protein-based vaccines will undoubtedly be major game-changers since they are not only safe, time tested, and highly efficacious, but also easy to produce, stable at higher temperatures, and generally very cost-effective.
But the lower-than-expected efficacy of 47% emerging from a large pivotal trial of the mRNA vaccine from CureVac, Germany, has seriously dampened hopes of its role in vaccination programmes in the European Union and elsewhere. The disappointing results underscore the risks and challenges for new vaccines, which will have to demonstrate efficacy against viral variants now prevalent all over the world.
Yet, new vaccines are being introduced at regular intervals. China has approved six vaccines and vaccinated a staggering 20 million people per day for more than a week in mid-June this year. Recently China has started vaccination of all minors using its own vaccines. There have been concerns about the efficacy of these vaccines in some Asian countries, including Indonesia and Thailand.
India, now & later
With 500 million (50 crore) vaccines already administered so far, India set its own record of vaccinating nearly 9 million people in a day on 21 June 2021. India’s vaccination programme so far has been mainly driven by Covishield of AstraZeneca/Serum Institute of India and Covaxin of Bharat Biotech accounting for over 87% and 12% of all vaccinations respectively. Sputnik V from Russia, which was approved in April 2021, is yet to make any sizeable contribution to the vaccination programme.
According to revised estimates, the vaccine programme in India hopes to procure 135 crore vaccines by December 2021. The overall average supply of all vaccines has hovered around 4 million per day for the last two months. Clearly, the supply will need to be more than twice the present rate.
It is hoped that both Covishield and Covaxin production will be scaled up, with Covaxin to be produced at multiple locations. Likewise, Sputnik V supply through imports, or through its production in India, is expected to fill the gap.
Manufacturing and approvals of protein-based vaccines of Novavax and Biological E will be crucial to the supply chain in India. Novavax has demonstrated safety and high efficacy of its vaccine and may seek approval for its use in India before it is approved elsewhere.
The DNA based vaccine developed by Zydus Cadila, which requires three shots for full vaccination, is also expected to be rolled out in the coming months. Biological E was also slated to manufacture the single-shot vaccine of Johnson & Johnson, which, however, is yet to be approved for use in India.
If all falls into place, India should be able to produce more than 1-2 billion doses of Covid vaccines by 2022. India is well known for its ability to produce high quality vaccines at affordable cost and it should hope to occupy its rightful position of the largest producer of vaccines, especially for developing countries.