"If a vaccine is 70 percent efficacious but offers 90 percent coverage, compared to a vaccine that is 90 percent efficacious, but offers only 50 percent coverage, I'll any day go for better coverage," said virologist Dr Shahid Jameel while decoding the various efficacy figures thrown up by the top three COVID-19 vaccines. He calls Oxford vaccine data ‘very good news’ for India and the developing world.
Oxford AstraZeneca vaccine's preliminary data from stage 3 trials indicated that it has 70.4 percent efficacy.
What does it mean in real terms? How does it compare to Pfizer and Moderna vaccines that show 95 percent efficacy? And do Bharat Biotech's claims on the indigenous Covaxin being at least 60 percent efficacious hold up? Is that good enough for you and I?
I put all these questions to Dr Jameel, Director at Trivedi School of Biosciences at Ashoka University.
“Just because a vaccine costs $35, it doesn’t mean its a better vaccine than one that costs $3,” says Dr Jameel.
Decoding Oxford Vaccine Efficacies 62%, 70.4%, 90%
Dr Jameel says that while the Oxford vaccine data is promising, it's still not as exciting as Pfizer and Moderna's efficacy of nearly 95 percent. However, there's a lot of science that indicates it still is very good news.
Oxford vaccine was given in two different dosages: One set received a 'low' shot as the first dose and a 'high' shot as the second dose. The second set received 'high' doses both times. He says it's surprising that the low dose produced better efficacy of 90 percent than the high dose that showed an efficacy of 62 percent. The Oxford team will be examining the data that showed better efficacy, and we'll know more shortly.
Efficacy Matters, Coverage Matters More
"90 percent is great, but I would any day take a vaccine that offers better coverage," said Dr Jameel. Explaining it further, he said, if there is a vaccine that offers 70 percent efficacy but a 90 percent coverage, it's a better bet for a country. Reasonable efficacy but a good coverage is very important, he added.
Despite Low Efficacy, It's the Best Bet for India
“First of all, Pfizer and Moderna vaccines will not be available in India. Let’s be very clear about it,” said Dr Jameel.
Dr Jameel, stating a simple fact there. These vaccines require very cold storage. Pfizer needs to be stored at -70 degree Celsius, requires specialised containers, transport, training and distribution. Moderna vaccine can be stored at -20 degree Celsius and can be kept in freezers of normal refrigerators, but again, those are not available everywhere.
Secondly, and this is the painful truth, these vaccines are just too expensive and have been pre-booked very heavily by first-world countries. For example in the UK, for a population size of 67 million, they have already pre-booked 325 million doses – five times their population. Similarly in Australia, for a population of 25 million, 34 million doses have already been booked.
The Oxford vaccine, on the other, has been undergoing phase 3 trials in India. The Serum Institute of India (SII) is already manufacturing these vaccines here. They have a capacity of 800 million doses a year, of which 400 million will be available to India. We have a large at stake in this vaccine.
Haves and Have-Nots: Do I Get a Raw Deal Because I live in a Developing Country?
Dr Jameel says that only because Moderna and Pfizer vaccines have 95 percent efficacy, it doesn't automatically mean they are better vaccines. Efficacy during a trial in a controlled environment is a different ball game than efficacy in a real-world situation. "If cold chain breaks down, we can't train enough people, if distribution is limited, it is of little value. I would not pay too much attention to this 70 vs 90 vs 95 percent efficacy."
“On the other hand, we know we live in an unequal world.”
Look at the cost differential, he adds. Pfizer and Moderna are selling in those countries that have pre-booked the orders at $25-35 per dose. Whereas, the Oxford vaccine is available at $3 - $4.
Given a Choice Among Moderna, Pfizer and Oxford Vaccines, Which One Should I Pick?
Dr Jameel repeated what he has been emphasising on – better coverage, affordable cost, and availability should determine what vaccine you choose. Getting a vaccine at a higher cost should not be a status symbol.
On a hopeful note, what these first 2-3 vaccines have proven is that all vaccines will work, because they essentially follow the same principle. Any news on vaccines is good news right now.
(The article was first published in FIT and has been republished with permission.)
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