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Pfizer vs Moderna vs AstraZeneca! Whose efficacy to trust?

New vaccines are rarely certified for efficacy above 90 per cent. Their efficacy improves as millions are vaccinated over decades. In fact, most vaccines get certified in the 40-60 per cent efficacy band

Manoj Sharma | November 27, 2020 | Updated 21:02 IST
Pfizer vs Moderna vs AstraZeneca! Whose efficacy to trust?

A sense of frustration is developing in the medical world over lack of uniformity in clinical trials of COVID-19 vaccine makers, which has resulted in rather implausible claims. Top vaccine makers Pfizer, Moderna have claimed efficacy of over 90 per cent. AstraZeneca, which is developing the vaccine with Oxford University, has made it worse by releasing multiple data points for the efficacy of its vaccine. Oxford-AstraZeneca's vaccine is the same vaccine that the Serum Institute is producing in India, and it's most likely to be the vaccine that most Indians will eventually get.

New vaccines are rarely certified for efficacy above 90 per cent. Their efficacy improves as millions are vaccinated over tens of years. In fact, most vaccines get certified in the 40-60 per cent efficacy band. Even a 70 per cent efficacy is considered excellent in the world of vaccines. The world's most powerful vaccine -- Measles -- has nearly 60 years of science and millions of vaccinations backing it to be called 94-95 per cent efficacious.

But vaccine makers are currently flashing high per centage figures because they have carried out tests on extremely small number of people. Pfizer's 'final efficacy analysis' involved only 170 patients, while Moderna had 95. AstraZeneca tested its vaccine on 131 patients. Once these vaccines get tested on thousands, the efficacy is expected to correct to a more reasonable figure.

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But since these vaccine makers started releasing data a few weeks back, what's become obvious is that there is a clear absence of uniformity at a regulatory level. The vaccine makers are in a race to make the vaccine first, and the experts are beginning to call them out.

In India, Executive Chairperson of Biocon Limited, Kiran Mazumdar Shaw, has expressed disappointment over zero regulatory uniformity in the clinical design of vaccines being developed across the world. She said the competition to be the first to win the vaccine development race has led to "chaotic clinical trials". This has posed various questions over the reliability of the clinical trial data of these companies, she said.

"Disappointed at zero regulatory uniformity in the clinical design of vaccines," the Biocon chief said.

Expanding further, Shaw said it's shocking to see "zero global regulatory alignments on simple things like RT-PCR testing post-vaccination for efficacy read out". While companies like Moderna and Pfizer only test symptoms, while AstraZeneca does it weekly, which is a better indicator, she added.

Shaw urged regulators to "wake up and give people more confidence".

Shaw's remarks reflect the current scenario where emboldened pharma firms indulge in a game of one-upmanship based on an alarmingly low number of trials. Sample this: Russia's Sputnik V had been tried on only 20 patients before its Gamaleya Institute claimed that it had developed the world's first coronavirus vaccine. The US pharma major Pfizer analysed clinical trial data of just 120 participants -- and later increased the number to 170 -- and another pharma company Moderna revealed the vaccine efficacy after studying data of 95 participants only.

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Pfizer-BioNTech's 9 November statement said it's Covid vaccine has attained 90 per cent efficacy. Two days later, Russia's Gamaleya Institute said its vaccine Sputnik V was one step better - 92 per cent.

Moderna, which is also developing its vaccine on mRNA technology, said its vaccine had shown 94.5 per cent efficacy. Then came another claim by Pfizer, which said the final analysis of its vaccine candidate suggests it is 95 per cent effective against coronavirus.

Already under pressure to join the coveted league of frontrunners, Swedish pharmaceutical giant AstraZeneca, which has partnered with Oxford University, released its interim analysis data on November 23, saying their vaccine has shown 70 per cent efficacy against the COVID-19 virus. The company, however, said a lower dosage level of its vaccine emerged as more effective, generating about 90 per cent efficacy.

This raised eyebrows over the disparity in its clinical trial results. AstraZeneca and the University of Oxford initially didn't reveal the error and other important details, leading to concerns over their transparency. Now the company plans to conduct an extra global trial to straighten out dubiety and confusion around favourable results in its current study.

Right through this phase, though, the world's toughest drug regulators, which are otherwise known for their zero-tolerance and harshest crackdowns against pharma companies - seems to have remained silent on vaccine developers' claims.

ALSO READ: AstraZeneca, Oxford vaccine shows 'strong response' in older adults

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