The first major study, conducted “in the real world” independently of the vaccine from Pfizer and BioNTech, showed that the injection was highly effective in preventing Covid-19. The good news comes at a time when several countries are eager to end restriction and reopen their economies.
Conducted two months after launching one of the world’s most ambitious vaccination plans in Israel, the study is a rich source of data and showed that two doses of Pfizer injection reduced symptomatic cases of Covid-19 by 94% in all age groups.
To date, most of the data on the vaccine’s efficacy has been obtained from controlled clinical trials, and how these results, with so many unpredictable variables, translate into the “real world” is uncertain.
The study, which involved about 1.2 million people – 600,000 who received the two recommended doses and a corresponding number of people who did not receive the injection – also found that a single injection was 57% effective against it after two weeks symptomatic infection was on data published and peer-reviewed in the New England Journal of Medicine this Wednesday. Preliminary data was released last week.
The results of the study, commissioned by the Clalit Research Institute, were similar to clinical studies with the vaccine, which found two injections to be 95% effective.
“We were surprised because we expected that in the real-world scenario, where the cold chain is not perfectly maintained and the population is older and sicker, we would not get as good results as in controlled clinical trials,” said Ran Balicer of the lead authors of the study, Reuters. “We have shown that the vaccine is effective in very different subgroups, in young and old, in people without comorbidities and in people with few comorbidities,” he added.
The study also suggests that the vaccine is effective against the coronavirus variant first identified in the UK. The researchers say they can’t find a specific level of effectiveness, but that variant was dominant in Israel at the time of the study. There is also insufficient data to assess the effectiveness of the South African variant.
Almost half the country has been vaccinated
Of the nine million citizens of Israel, a nation with a universal health system, nearly half have already received the first dose and a third have received two doses of the vaccine since the vaccination schedule began on December 19. These numbers make Israel the ideal place to test the vaccine’s true capacity and, consequently, its ability to contain the pandemic.
Almost 600,000 people who received the vaccine were “closely related” to around 600,000 others who did not receive the injection and showed very similar characteristics in terms of gender, age, but also comorbidities and localization. Comparing the two groups, the authors show that vaccination reduced symptomatic cases of Covid-19 by 94%, severe cases of the disease by 92%, and hospital admissions by 87%. These rates apply to protection given at least seven days after the second injection.
“However, a very significant effect was already observed before the second dose,” Noam Barda, one of the two main authors of the study, told France Press with an effectiveness of 57% in Covid-19 cases with symptoms and 62% in serious patient cases .
The vaccine was also 72% effective in preventing Covid-19 deaths after the first dose, but its small number in this study makes this result less reliable. The study, published this Wednesday, is the first analysis of a national vaccination strategy against Covid-19 that has been peer-reviewed.
The latest data from the Weizmann Institute shows a dramatic decline in disease circulation since vaccination began, easing the rules of the third national restriction and reopening some industries.
While some places are open to everyone, others are only open to people with the ‘green pass’, which means they received the second dose of the vaccine or recovered from the disease at least a week ago.