Covid: Israeli vaccination expert calls UK second-jab delay plan ‘very optimistic’

A hospital director in Israel, which is leading the world’s coronavirus inoculation race, has questioned the UK’s decision to delay administering a second dose of the Pfizer-BioNTech Covid vaccine to patients by up to 12 weeks.

Ronni Gamzu, who runs Tel Aviv’s Sourasky hospital, said that British scientists’ claim that the jab was 89 per cent effective even after only one dose was “very optimistic” and not matched in Israel’s “real-world findings”.  

Israel is following Pfizer’s advice to give the second dose of the vaccine three weeks after the first. 

However, UK figures, including chief medical officer Chris Whitty, have backed a delay in second vaccine doses, claiming it allows more people to be given some level of protection more quickly.

The UK Joint Committee on Vaccination and Immunisation (JCVI) has previously said: “With most vaccines, an extended interval between the prime and booster doses leads to a better immune response to the booster dose.

“The committee advises initially prioritising delivery of the first vaccine dose as this is highly likely to have a greater public health impact in the short term.”

Dr Gamzu told Sky News that he acknowledged a “clear logic” behind the UK strategy if a country was facing vaccine supply issues. “If you are short of vaccines, this [gap in doses] is a good idea,” he said.

“We believe that if you take the booster shot, even after six weeks, then you will have an effect, the effect is coming and growing gradually.”

However, he said the UK expectation of an 89 per cent reduction in infections after only one dose was “very optimistic”.

Professor Ran Balicer, a physician, epidemiologist and chief innovation officer for Clalit, the largest health care provider in Israel, said the country had “already covered [vaccinated] some 25 per cent of our population and over 75 per cent above the age of 60 in the last four and a half weeks”.

“We are one of the first countries to be able to witness the sheer impact of vaccinating such a large proportion of the population,” the World Health Organisation adviser added. 

Asked about the UK’s delayed-dose strategy, he said: “We could not see 89 per cent reduction in the data we reported.”

The JCVI has already made moves to justify the lengthy Pfizer dose gap by comparing it to trial data from the Oxford-AstraZeneca vaccine – where it was proven that a longer gap of two to three months led to a greater immune response.  

During the Oxford study, 59 per cent of the UK trial participants received their second dose between nine and 12 weeks after the first. Results published in the Lancet journal showed that vaccine efficacy 14 days after a second dose was higher in the group that had more than six weeks between the two doses than in the group that had less.

“There is evidence that a longer interval between the first and second doses promotes a stronger immune response with the AstraZeneca vaccine,” the committee has said before.

“There is currently no strong evidence to expect that the immune response from the Pfizer-BioNTech and AstraZeneca vaccines differ substantially from each other.”

While this is true, there is also currently no strong evidence to suggest the lengthy gap proven to work between Oxford’s vaccine doses would work between Pfizer’s. 

When the UK government announced in late December its decision to extend gaps between doses, Pfizer issued a warning over what it called “alternative dosing”.

“There is no data to demonstrate that protection after the first dose is sustained after 21 days,” a spokesperson said.