THE HUMAN BODY is quite marvellous in how it already has all the tools and equipment needed to defend itself. The reason it falls prey to disease is often only a question of correct identification. Should that information be clear, then it churns out more than enough soldiers to kill the opposing army. This has been the principle in use ever since vaccines were first made. Two separate developments have shown how mankind has managed to now tweak this behaviour further in finding an answer to the novel coronavirus. Such news came in rapid succession, from pharmaceutical companies Pfizer and Moderna announcing how their Phase 3 vaccine trials are turning out to be resounding successes.
On November 18th, Pfizer put out a press release that said: ‘The first primary objective analysis is based on 170 cases of COVID-19, as specified in the study protocol, of which 162 cases of COVID-19 were observed in the placebo group versus 8 cases in the BNT162b2 group. Efficacy was consistent across age, gender, race and ethnicity demographics. The observed efficacy in adults over 65 years of age was over 94%.’ In plainspeak, it divided 43,000 people into two groups, and gave the vaccine and a placebo to each group. And then monitored them until 170 of them got Covid. Of the group that got the placebo, 162 became infected. Of that which got the actual vaccine, only eight were infected. That the vaccine works to an extraordinary degree was clear. They also found that it was safe, had negligible side-effects like fatigue or headache, and worked across all categories, from ‘age, gender, race and ethnicity demographics’.
Moderna, too, announced early Phase 3 results with similar effective results. In its case, out of 30,000 volunteers who were given the vaccine and placebo, 95 contracted Covid. But of those, 90 were on the placebo. Only five who were on the vaccine got infected. Moderna, in fact, started working on a vaccine in 2020 beginning within weeks of Covid going global became known. This was possible because both companies are using a new and revolutionary process to create the vaccines that crunched what would usually have taken years or even decades. These vaccines are made using mRNA or messenger RNA, which takes an instruction to body cells where ribosomes, protein making factories within, produce harmless bits of the spikes that define the Covid-19 virus. This, in turn, leads to the body creating antibodies. So when the actual virus strikes, the army is ready. It knows exactly who and where the enemy is.
It is an ingenious technique that also allows for large quantities to be manufactured quickly. The Pfizer press release said it expects ‘to produce globally up to 50 million vaccine doses in 2020 and up to 1.3 billion doses by the end of 2021.’ But India may not have much cause to celebrate from these classes of vaccines. For one, other countries already have deals that will get them first access to the manufactured doses. India will be way off in the queue. Plus, the problem with mRNA vaccines is that they require very cold freezing temperatures to store. Developed countries that have a cold chain infrastructure can do it, but India has very little of it. So while we have enormous experience in immunisation and vaccination programmes, they are based on traditional vaccines. Fortunately, there are plenty of other suitable vaccine candidates on the horizon.
Along with Pfizer and Moderna, interim results of Phase 3 trials of another vaccine came out, the Russian-made Sputnik V. It too had an efficacy of over 90 per cent. The journal Nature reported: ‘The Gamaleya National Center of Epidemiology and Microbiology in Moscow and the Russian Direct Investment Fund said that an interim analysis of 20 COVID-19 cases identified among trial participants has found that the vaccine was 92% effective.’ A batch of Sputnik V has just arrived in India for Phase 2 trials involving 100 volunteers. Largescale Phase 3 will follow after that. The vaccine uses a different process using an adenovirus. Genetic material of Covid-19 is latched onto another harmless virus, a vector, and introduced into the human body, which then leads to Covid antibodies being produced.
Another adenovirus vaccine that India is banking on in a major way is being helmed by AstraZeneca and Oxford University whose website explains how it works: ‘The ChAdOx1 vaccine is a chimpanzee adenovirus vaccine vector. This is a harmless, weakened adenovirus that usually causes the common cold in chimpanzees…The Oxford vaccine contains the genetic sequence of this surface spike protein (of Covid-19). When the vaccine enters cells inside the body, it uses this genetic code to produce the surface spike protein of the coronavirus. This induces an immune response, priming the immune system to attack the coronavirus if it later infects the body.’ The Pune-based Serum Institute, has already started largescale production of this vaccine in anticipation of it being effective, and for India alone it might have 100 million doses by the end of December.
There are also other candidates. Speaking to the media, VK Paul, chairman, NITI Aayog, said in his weekly briefing that there are five vaccines whose trials are going on in the country and they would be better candidates for its needs than Pfizer or Moderna. The Indian Express quoted him saying that these were ‘easy platforms’ and the ‘availability of doses is also extremely high’. The report added, ‘On the in-country vaccine trials, Paul said, “Currently, phase-3 of vaccine candidate tested by Serum Institute is almost complete and the follow-up is currently under way. Bharat Biotech has just begun the phase-3 trials; Zydus Cadila has completed phase-2 trials, and Russian Sputnik -V being tested in collaboration with Dr Reddy will begin phase two or three next week. Biological E is conducting an early phase 1-2 trial.”’
Meanwhile, even the Pfizer and Moderna vaccines will have to be evaluated for long-term side-effects. Then there is the question of how long the immunity lasts. Because of the haste with which these vaccines will have to be okayed for use, many such questions will get answered on the go.
But it is looking increasingly probable that by early 2021 vaccine rollouts will begin. Getting everyone in the world vaccinated will still be a long haul of years but, as Dr Anthony Fauci, who is leading the US efforts against Covid-19 commented recently, results have belied earlier expectations. He told AFP in an interview after the Moderna news: “I must admit that I would have been satisfied with 70 or at the most 75 per cent efficacy. The idea that we have a 94.5 per cent effective vaccine is stunningly impressive. It is really a spectacular result that I don’t think anybody had anticipated would be this good.”