Pfizer vaccine blocks 94 per cent of asymptomatic cases, study finds

Israelis attending a 'green pass concert' for those who have been vaccinated

Credit: Jack Guez/Getty Images

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The Pfizer vaccine blocks 94 per cent of asymptomatic cases, an Israli study has shown, reigniting hopes herd immunity can be reached.

The Israeli ministry of health found that the Pfizer vaccine has an efficacy of 97 per cent against disease and death and 94 per cent against infection without symptoms.

The figures, which have not yet been peer-reviewed by scientists, were welcomed by scientists as they will help the UK reach herd immunity and eventually relax social distancing rules. 

Israel is the first country to have vaccinated more than half its population, which it has done with Pfizer/BioNTech. 

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As of Wednesday, 55 per cent of its nine million population had been given at least one dose of the Pfizer vaccine, and 43 per cent had received a second dose.

Dr Peter English, a retired consultant in communicable disease control, said the results are “very good news indeed”. 

“The fact that the vaccine not only prevents disease, but also infections (and therefore, presumably, transmission) is particularly encouraging news,” he said. 

“If the vaccine can prevent transmission with over 90 per cent efficacy, we are much likely to achieve vaccine-induced population immunity (herd immunity), and thus – eventually to drive the effective R number below one through vaccination alone, which will (in due course) allow us to relax social distancing and other restrictions.”

He added: “It is great to see yet more good news on Covid-19 vaccines from Israel – a country which has been very quick off the mark in vaccinating its population. 

“They have done an excellent job on analysing the real-world effectiveness of the vaccine from these data.”

Pfizer/BioNTech declined to release the finer details of the results, which will be published in a peer-reviewed journal in due course. 

But Pfizer said the data confirmed the 95 per cent efficacy it had found in its phase three trials of the vaccine.