December 06, 2020

Some Good News on the Vaccine Front but Challenges Remain

Prabir Purkayastha

THE scientific community has responded to the Covid-19 pandemic in a way that would have been thought impossible earlier. Within only 12 months, we are now likely to have a set of vaccines for Covid-19. This is an astounding achievement, as the fastest vaccine development till date was mumps which took nearly four years. Equally important is that the first four vaccine candidate frontrunners – Pfizer-BioNTech, Moderna, Oxford-AstraZeneca, Gamaleya – have all shown efficacy well-beyond the target of 50 per cent success rate set by the regulatory agencies. Pfizer-BioNTech has also been cleared by UK for emergency use, as was Gamaleya earlier by Russia. These early results provide hope that lives can slowly return to normal, if – and this is a big if – we handle mass vaccination of the people at a pace and to an extent that we have never done before.

If vaccines could be developed in such a short time using many different vaccine platforms, why is it that infectious diseases still affect two-thirds of the global population? Why have the vaccines not been a priority for the Big Pharma till Covid-19, which brought home the message that microbes have no borders?

Though four vaccine makers have announced preliminary results through press statements of their success, another 20 odd vaccines are going through phase 3 trials, and some of them likely to announce positive results as well. The vaccine candidates use different kinds of technologies. Some like BioNTech-Pfizer and Moderna are using completely novel technologies, while some others, like Bharat Biotech and Sinovac, use inactivated virus as vaccines, that has been with us for more than a hundred years. If the bulk of the vaccine candidates pass the bar of 50 per cent efficacy in the trials set by regulators, the question then will be which ones do we then use for our people? Do we make efficacy the only criterion, or do we look at the logistics – the ultra-cold chain temperature of some of the vaccines like Pfizer-BioNtech and Moderna – compared to simple refrigeration? Or look at how quickly we can start vaccinating the people and at what costs?

Pfizer-BioNTech and Moderna have both claimed above 90 per cent efficacy. These are preliminary figures and based on a small number of infections in the double-blind trials. The Russian Gamaleya vaccine has also claimed more than 90 per cent efficacy, though again on small numbers.

The Oxford-AstraZeneca numbers are a little complicated. It had a plan for two full doses with a 28 days gap in between, but due to a mistake, gave a small fraction of the volunteers a half first dose, though a normal, full second dose. The normal regime of two full doses showed the efficacy of 62 per cent while the half-full dose combination showed a 90 per cent efficacy, and according to AstraZeneca a combined efficacy of 72 per cent.

All these numbers of vaccine efficacy have done wonders for Pfizer and Moderna's stock prices. As did Gilead's Remdesivir, after initial reports of successes based on trials with a small number of cases. As a larger trial showed, Remdesivir's favourable results were not borne out by larger trials. Nevertheless, with four vaccines showing early promise, we can be hopeful of a set of successful vaccines being available by early 2021.

In this context, a recent "adverse event" in the Indian trials of the Oxford-AstraZeneca vaccine being conducted by Serum Institute and Indian Council of Medical Research (ICMR) has drawn media attention. A volunteer in the trial developed serious medical problems needing hospitalisation. Even after he was released, he continued to have problems and has sued the Serum Institute. Serum Institute and ICMR have stated that the Ethics Committee of the trial has examined the issue and found that the adverse event did not have any relations to the vaccine trial. They also stated that it was only after the requisite procedures were completed and clearances received that the vaccine trial was resumed. According to official sources reported in the media, a probe initiated by the Drugs Controller General of India has found that the alleged "adverse event" was not related to the vaccine shot administered to the volunteer.

Vaccine trials involve hundreds of thousands of healthy volunteers. During the trials, some of them will fall ill, as it happens in any large group of people. The question is whether the illness is connected to the vaccine trial, or due to other reasons. An earlier incident with the Oxford-AstraZeneca vaccine had led to a temporary halt of the trials, and only after determining that it was not due to the vaccine, the trials resumed. In Brazil, a trial using a vaccine candidate from Sinovac, China, was temporarily halted for two days after a volunteer died. It was resumed after it was found that the death was due to a drug overdose, and completely unrelated to the vaccine trial.

Such "adverse events" are routine in any vaccine development, and we would be very surprised if, in the normal course of events, nobody in such large vaccine trials, falls ill among the volunteers. It is important in such cases that the regulatory authority, in India the DCGI, responds quickly instead of letting the issue balloon up as it did in the media.

In the current anti-science climate in which all kinds of wild beliefs – from the efficacy of cow's urine to 5G technology causing Covid-19 – are propagated, we need to address such issues quickly. The US is notorious as the only country in the world that seems to have a strong anti-vaccine campaign and the rise of vaccine scepticism there. The number of people who say that even if a vaccine is available, they will not get themselves vaccinated, is the highest in the US. It is worrying that there are now small groups of anti-vaxxers, drawing their inspiration from this loony fringe of US politics, who are active in different parts of the world. They cloak their arguments with a blend of anti-state, anti-big business rhetoric, peppered with seemingly scientific studies, which on face value seem credible. We could laugh at these conspiracy theories if the results of such campaigns are not so dangerous. Even if a fraction of the people do not get vaccinated, it means no herd immunity, and continued infections, as shown by the recurrence of measles in the US.

On a different tack, assuming that within a few months, many vaccines would have passed the efficacy bar of 50 per cent, how are different countries placed in getting the vaccines for its people?

Here vaccine nationalism has reared its ugly head. The rich countries, numbering 13 per cent of the world's population, have either already bought or booked about 55 per cent (9.8 billion doses) of the current vaccine manufacturing capacity. This is two to three times their need, as they are not sure which vaccine will succeed and they want to hedge their bets at this stage. Among the middle or lower-middle-income countries, India and Brazil are relatively better placed because of their large indigenous manufacturing capacities. The low-income countries have only WHO-backed GAVI-CEPI vaccine alliance, and the Covax facility to provide them with vaccines.

China has joined the Covax facility and promised that its vaccines if successful, will be considered as "global public good" and available to many countries. They have also committed a large number of vaccine doses to countries that are partnering Chinese companies and institutions for clinical trials in these countries.

The WHO-backed Covax facility requires 2 billion dollars to provide vaccines to cover 20 per cent of the people in low-income countries. Till date, it has been able to raise only $800 million. With the rich countries booking vaccine capacity in advance, the poorer countries will not be able to get enough vaccines to cover their population till 2023-2024.

The task of vaccinating the bulk of our population is not a scientific challenge but a public health and a societal challenge. And as a society, we have done poorly on both these fronts. Even with this warning, most countries were completely unprepared for the challenge of the pandemic. While the US was busy attacking China and WHO for what Trump called the Wuhan virus, the reality is that despite some of the best medical institutions in the world, its public health system collapsed during the pandemic. Countries such as India, Brazil, UK – to name a few – have not done much better either. So the question: with the vaccine, will we address the public health challenge of Covid-19 better? And as long as Covid-19 exists in the world, no country will be safe. Remember, microbes do not respect borders?