Jerusalem – The first dose of the Pfizer-BioNTech Covid-19 vaccine is 85 per cent effective against coronavirus infection two to four weeks later, according to a study published in The Lancet medical journal.
A study conducted by Israel’s Sheba Medical Center and published on Friday (Feb 19) in The Lancet medical journal provided information on the Pfizer vaccine’s effectivity.
Among 7,214 hospital staff who received the first dose in January, there was an 85 per cent decrease in symptomatic Covid-19 cases within 15 to 28 days. Furthermore, there was an overall 75 per cent reduction of infections, including asymptomatic cases detected.
The study focused on more than 9,000 medical staff at the hospital located near Tel Aviv. From the group, 170 were diagnosed with Covid-19 infection after tests were conducted only on those with symptoms or who came into contact with coronavirus carriers.
Out of the 170 individuals, 52 per cent were found not to have the Covid-19 vaccine.
The Sheba study then calculated that the vaccine was 47 per cent effective between one and 14 days after vaccination and 85 per cent after 15 to 28 days.
Professor Gili Regev-Yochay, the co-author of the study, told a small group of journalists, “What we see is a really high effectiveness already right after two weeks, between two weeks and four weeks after vaccine, already high effectiveness of 85 per cent reduction of symptomatic infection.”
Despite the vaccine being “amazingly effective”, Prof Regev-Yochay noted that scientists are still studying whether those who have completed the vaccination process could still transmit the virus to others.
“That is the big, big, question. We are working on it. This is not on this paper, and I hope we will have some good news soon,” she said.
Another Israeli study indicated that there was a 94 per cent drop in symptomatic Covid-19 cases among 600,000 people who received both doses of the Pfizer vaccine.
According to the health maintenance organisation (HMO) Clalit, the same group also showed they were less likely to develop severe illness from the virus by a rate of 92 per cent.
“It shows unequivocally that Pfizer’s coronavirus vaccine is extremely effective in the real world a week after the second dose, just as it was found to be in the clinical study,” said Clalit’s chief innovation officer Ran Balicer on Feb 14.
Mr Balicer also noted that the data indicates Pfizer’s vaccine would be more effective two weeks and later after the second shot./TISG
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