Pfizer vaccine less effective against Delta variant, Israeli study finds 6 months ago

Pfizer vaccine less effective against Delta variant, Israeli study finds

It is still 93 per cent effective against serious illness and hospitalisation

A study in Israel has found the BioNTech/Pfizer vaccine is less effective at halting the spread of the Delta variant than previous strains of Covid-19.


Data collected over the last month has suggested that the vaccine is 64 per cent effective at preventing infection among those who have received both doses of the jab. In comparison, the vaccine's effectiveness against previous strains of the virus was estimated to be 94 per cent.

The preliminary study was carried out by Israel's health ministry. The research did find that the Pfizer jab is still 93 per cent effective against serious illness and hospitalisation.

Professor Nadav Davidovitch, who sits on the Israeli government's expert advisory committee on Covid-19, pointed out that the study was based on "preliminary" figures.

He said: "Delta is a lot more infectious, but appears to not lead to as much serious illness and death, especially given that we now have the vaccine."

The Financial Times reports that cases have been rising in Israel since the country lifted all remaining Covid-19 restrictions on June 1. As of Monday, the country had almost 2,600 active cases, more than double that of the previous week. However, the health ministry said that only 35 of these were considered seriously ill.

Earlier this year, Public Health England found that the Pfizer vaccine offered 88 per cent protection against symptomatic infection against the Delta variant, compared to 93 per cent protection against the Alpha variant first identified in Kent. The protection offered by the Oxford-AstraZeneca vaccine against the Delta variant was lower, at 66 per cent protection.


Israel has now started to reintroduce some minor social distancing measures, with face masks now reimposed as a requirement for indoor gatherings and public transport. The government is considering additional restrictions as well, including limits on large public gatherings.

Davidovitch said that he does not think the virus will hit the same levels in Israel as it is in the UK, saying: "I don't believe it will be like the UK.

"We have more vaccinated people here, Pfizer seems to provide better defence than [AstraZeneca], and I don’t believe the government will allow the virus to run rampant. We have to be proportional in our response."

On Monday, Boris Johnson announced that all remaining social distancing measures are set to be lifted in England from July 19, despite rising case numbers across the country.