Symptomatic cases of COVID-19 are dropping by 94% after two doses of the Pfizer vaccine, according to the largest study of real-world data from Israel.
Research by Clalit, the biggest healthcare provider in Israel, shows that the Pfizer vaccine is equally effective for all age groups, with preliminary data showing a 94% drop in symptomatic cases and a 92% drop in serious cases.
Clalit analysed 1.2 million people - 600,000 of who had received two doses of the Pfizer jab and the same number who had not.
Israel's detailed digital collection of patient data allowed scientists to match the two groups.
According to Clalit, the patients were matched according to their general health, where they live, their risk of infection and their risk of becoming seriously ill.
Professor Ran Balicer, founding director of the Clalit Research Institute said: "It's now unequivocally clear that Pfizer's coronavirus vaccine is extremely effective in real life a week after the second dose, just as was found in the clinical trials."
Israeli scientists are under pressure to share peer reviewed studies with other countries.
But Prof Balicer warned the new study was still based on preliminary data, telling Sky News: "We have no manuscript that we can share at this time."
He stressed, though, that the study does show the vaccine is highly effective in preventing serious illness. Initial clinical trials were unable to prove this.
Israel has provided the world examples of how to fight coronavirus, but also warnings of mistakes to avoid.
The country put in place a swift and draconian early lockdown in March 2020 but then opened up the country far too quickly, seeing a massive spike in cases last year.
The rate of infection continues to be very high and adherence to lockdown rules is patchy.
But the vaccine programme has been the most successful in the world with nearly 40% of the population now vaccinated.
The latest concern among Israeli officials is the significant drop-off in vaccine uptake in the past two weeks as they try to encourage younger people to have the jab.
The publication of the latest study is designed in part to prove to those reluctant to get vaccinated that it does work.
Dr Guy Choshen, the coronavirus medical director at Tel Aviv's Ichilov Hospital, told Sky News he is concerned.
"We see an increase now in the percentage of the younger patients in our ICU," he said.
"(There are) less and less older patients - older than 60. And most of the patients that are admitted to the hospital are not vaccinated. So that's another example of the efficacy of the vaccine."
Israeli Health Minister Yuli Edelstein is proposing banning people who cannot prove they have been vaccinated from shops, malls, restaurants and gyms.
On Friday, Mr Edelstein said: "The gyms will reopen soon. With one small decision of yours, you can decide if you will join in the festivities or remain behind. All you have to do is get vaccinated. One small step for you, one big step for the country."
The Israeli government is proposing a carrot and stick approach, providing benefits to local government departments based on vaccination rates and implementing tourism agreements with other countries.
Proposals are also in place to require high density workplaces to ensure their staff are vaccinated.