'More great news': Pfizer covid vaccine found 94% effective in real world2 min read . Updated: 25 Feb 2021, 08:12 AM IST
- Up until now, most data on the efficacy of COVID-19 vaccines has come under controlled conditions in clinical trials
The Pfizer Covid-19 vaccine proved 94 percent effective in a huge real world study published Wednesday that involved 1.2 million people in Israel, confirming the power of mass immunization campaigns to end the coronavirus pandemic. Up until now, most data on the efficacy of COVID-19 vaccines has come under controlled conditions in clinical trials, leaving an element of uncertainty over how results would translate into the real world with its unpredictable variables.
The research in Israel - two months into one of the world's fastest rollouts, providing a rich source of data - showed two doses of the Pfizer shot cut symptomatic COVID-19 cases by 94% across all age groups, and severe illnesses by nearly as much.
The study of about 1.2 million people also showed a single shot was 57% effective in protecting against symptomatic infections after two weeks, according to the data published and peer-reviewed in the New England Journal of Medicine on Wednesday.
The results of the study for the Clalit Research Institute were close to those in clinical trials last year which found two doses were found to be 95% effective.
The study also suggests the vaccine, developed by U.S drugmaker Pfizer and Germany's BioNTech, is effective against the coronavirus variant first identified in the UK. Researchers said they could not provide a specific level of efficacy, but the variant was the dominant version of the virus in Israel at the time of the study.
The research did not shed light on how the Pfizer shot will fare against another variant, now dominant in South Africa, that has been shown to reduce the efficacy of other vaccines.
Of the nine million people in Israel, a nation with universal healthcare, nearly half have received a first dose, and a third have received both doses since the rollout began on Dec. 19.
This made the country a prime location for a real-world study into the vaccine's ability to stem the pandemic, along with its advanced data capabilities.
The study examined about 600,000 vaccinated people against the same sized control group of unvaccinated people. Researchers at Harvard T.H. Chan School of Public Health, Harvard Medical School and Boston Children's Hospital also collaborated.
"This is more great news, confirming that the vaccine is around 90% effective at preventing documented infection of any degree of severity from 7 days after the second dose," said Peter English, a British government consultant in communicable disease control.
"Previous recently studied papers from Israel were observational studies. This one used an experimental design known as a case-control study ... giving greater confidence that differences between the groups are due to their vaccination status, and not to some other factor."
The good news came as Ghana became the first country to receive shots under the global Covax scheme, paving the way for poorer nations to catch up with wealthier parts of the world.
"At last!" WHO chief Tedros Adhanom Ghebreyesus said in a tweet.
The WHO is one of several organizations behind Covax, which aims to deliver at least two billion doses globally by the end of the year.
More upbeat data meanwhile emerged about Johnson & Johnson's single-shot vaccine, which was shown to be highly effective against severe Covid-19, including newer variants, in detailed data released by the US regulator.
The vaccine is likely to be authorized soon, making it the third available in the hardest-hit country.
US biotech firm Moderna also announced its new Covid vaccine candidate aimed at the dangerous South African coronavirus variant had been shipped to government labs for testing.
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