The Pfizer Covid-19 vaccine proved 94 percent effective in a huge real-world study published on February 24 that involved 1.2 million people in Israel confirming the power of mass immunization campaigns to end the coronavirus pandemic.
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.
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 percent 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 percent 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 percent 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.
However,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.