“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.
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.
“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.