Covid-19: Study of 1.2 million shows Pfizer shot highly effective

Protective benefit of vaccine confirmed in Israeli study involving 1.2 million people

JERUSALEM The first big real-world study of the Pfizer-BioNTech vaccine to be independently reviewed shows the shot is highly effective at preventing Covid-19, in a potentially landmark moment for countries desperate to end lockdowns and reopen economies.

The study in Israel covered 1.2 million people.

The paper, published in the New England Journal Of Medicine on Wednesday, demonstrated there is likely a strong protective benefit against infection, a crucial element in breaking onward transmission.

"The fact that the vaccines worked so well in the real world... really does suggest that if the nations of the world can find the will, we now have the means to end Covid-19 forever," said virologist Ben Neuman from Texas A&M University.

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 showed two doses of the Pfizer shot cut symptomatic Covid-19 cases by 94 per cent across all age groups, and severe illnesses by nearly as much.

A single shot was 57 per cent effective in protecting against symptomatic infections after two weeks.

The results of the study for the Clalit Research Institute were close to those in clinical trials last year, which found two doses 95 per cent effective.

"We were surprised because we expected that in the real-world setting, where cold chain is not maintained perfectly and the population is older and sicker, that you will not get as good results as you got in the controlled clinical trials," senior study author Ran Balicer said.

"But we did and the vaccine worked as well in the real world."

The study also suggests the vaccine is effective against the variant first identified in Britain, but did not shed light on how the Pfizer shot will fare against the South African variant that has been shown to reduce the efficacy of other vaccines.

Meanwhile, people in England who have received two doses of the Pfizer vaccine are generating strong antibody responses, researchers said.

An Imperial College London survey showed 87.9 per cent of people over the age of 80 tested positive for antibodies after two doses of the Pfizer-BioNTech vaccine, rising to 95.5 per cent for those under the age of 60 and 100 per cent in those aged under 30.

More than 154,000 participants took part in Imperial's home surveillance study. - REUTERS, AFP