The first large, independently reviewed real-world study of the Pfizer / BioNTech vaccine shows that the injection is highly effective in preventing Covid-19, in a potentially historic time for countries desperate to end lockdowns and reopen. economies.
So far, most of the data on coronavirus vaccines has been obtained under controlled conditions in clinical trials, leaving an element of uncertainty as to how the results would translate in the real world.
Research in Israel, two months after one of the world’s fastest launches, which provides a rich source of data, showed that two doses of the Pfizer injection reduced symptomatic cases by 94% in all age groups and serious diseases in almost the same amount.
The study of about 1.2 million people also showed that a single injection was 57% effective in protecting against symptomatic infections after two weeks, according to data published and peer-reviewed in the New England Journal of Medicine on Wednesday.
The study results for the Clalit Research Institute were close to those from last year’s clinical trials that found two doses were 95% effective.
“We were surprised because we expected that in the real world environment, where the cold chain is not perfectly maintained and the population is older and sicker, it will not get as good results as it did in controlled clinical trials,” senior study author Ran Balicer told Reuters. “But we did it and the vaccine worked in the real world as well.”
“We have shown that the vaccine is just as effective in very different subgroups, in the young and in the elderly in those with no comorbidities and in those with few comorbidities,” he added.
The study also suggests that the vaccine, developed by US pharmaceuticals Pfizer and German BioNTech, is effective against the variant of the coronavirus first identified in the UK. The researchers said they could not provide a specific level of effectiveness, but the variant was the dominant version of the virus in Israel at the time of the study.
The research shed no light on how Pfizer’s injection will fare against another variant, now dominant in South Africa, which has been shown to reduce the effectiveness of other vaccines.
Of the nine million people in Israel, a nation with universal health care, nearly half have received a first dose and a third have received both doses since the launch began on December 19.
This made the country a prime location for a real-world study of the vaccine’s ability to stop the pandemic, along with its advanced data capabilities.
The study looked at about 600,000 vaccinated people versus the same-size control group of unvaccinated people. Researchers from Harvard TH Chan School of Public Health, Harvard Medical School and Boston Children’s Hospital also collaborated.
“This is great news, as it confirms that the vaccine is around 90% effective in preventing documented infections of any degree of severity seven days after the second dose,” said Peter English, UK government consultant on control of communicable diseases.
“Previous work recently studied from Israel were observational studies. This one used an experimental design known as a case-control study … giving greater confidence that the differences between the groups are due to their vaccination status and not to some other factor ”.
The study published Wednesday was the first analysis of a national Covid vaccination strategy to be peer-reviewed. It also offered a more detailed look at how the vaccine was doing at weekly intervals, while comparing people who received the vaccine with unvaccinated people with similar medical backgrounds, sex, age and geographic characteristics.
Other research centers in Israel, including the Weizmann Institute of Science and the Israel Institute of Technology, have shared several studies in recent weeks showing that the vaccine is effective.
At least three studies in Israel have also suggested that the vaccine may reduce the transmission of the coronavirus, but the researchers cautioned that larger studies must be conducted to draw clear conclusions.