Eight-week gap seen as sweet spot for Pfizer jab antibodies

A longer gap between first and second doses of SLOTXO the Pfizer-BioNTech Covid vaccine makes the body's immune system produce more infection-fighting antibodies, UK researchers have found.

The government-funded work is published in a pre-print paper not yet peer reviewed.

Experts say the findings support Britain's decision on dosing intervals.

And an eight-week gap may be the sweet spot for tackling the Delta variant of Covid now dominating the UK.

Rising infections The vaccine was originally authorised for a three-to-four-week gap between doses - but the UK extended it up to 12 weeks at the end of 2020.

It was a pragmatic move by government to get more of the population quickly jabbed with at least one dose.

At the time, the UK was experiencing a second wave of Covid and, with limited vaccine stocks, was in a race against the virus.

More recently, because of rising infections caused by the new Delta variant, first identified in India, the interval changed to eight weeks, to hasten second jabs that offer people the best protection against Covid-19.

For the study, the researchers compared the immune responses of 503 NHS staff who received their two shots at different intervals in late 2020 and early 2021, when the Alpha Covid variant, first identified in Kent, was rapidly spreading.

'Protect yourself' Vaccines Minister Nadhim Zahawi said: "The findings from this latest Pitch study are hugely significant not just for the UK but for the world, helping us better understand the mechanics behind our immune response to Covid-19 and the importance of getting both doses of the vaccine.

"As we raced to offer a vaccine to all adults, we took the [Joint Committee on Vaccination and Immunisation] JCVI's advice to shorten the dosing interval from 12 to eight weeks, to help protect more people against the Delta variant.

"This latest study provides further evidence that this interval results in a strong immune response and supports our decision.